219 F.3d 1 (1st Cir. 2000)
UNITED STATES OF AMERICA, Appellee,v.CARLOS ALBERTO BERRIO-CALLEJAS, Defendant, Appellant.
No. 98-2188
United States Court of Appeals  For the First Circuit
Heard Aug. 4, 1999.Decided July 13, 2000.

APPEAL FROM THE UNITED STATES DISTRICT COURT FOR THE DISTRICT OF PUERTO RICO. Hon. Jaime Pieras, Jr., Senior U.S. District Judge.
Edgardo Rodriguez-Quilichini, Assistant Federal Public  Defender, with whom Joseph C. Laws, Jr., Federal Public Defender,  was on brief for appellant.
Camille Velez-Rive, Assistant United States Attorney, with  whom Guillermo Gil, United States Attorney, and Jorge E. Vega-Pacheco, Assistant United States Attorney, were on brief for  appellee.
Before: Selya, Circuit Judge, Cyr, Senior Circuit Judge, and Boudin, Circuit Judge.
CYR, Senior Circuit Judge.


1
Like many before it, this  appeal involves various violations of Federal Rule of Criminal  Procedure 11(c) & (d).1  Nevertheless, appellant has not  demonstrated a total failure to comply with a "core" Rule 11  concern and, after assessing the errors committed by the district  court, we are satisfied that they are harmless or, in one instance,  conspicuously waived on this appeal.  See, e.g., United States v. Cotal-Crespo, 47 F.3d 1, 4-5 (1st Cir. 1995); United States v. Allard, 926 F.2d 1237, 1244-45 (1st Cir. 1991); see also Fed. R.  Crim. P. 11(h).


2
Appellant was charged by information, in the United  States District Court for the District of Puerto Rico, with  violating 21 U.S.C. § 841(a)(1) by knowingly possessing  approximately 1,692.8 grams of cocaine base, with intent to  distribute.  After pleading guilty pursuant to a written plea  agreement, he was sentenced, inter alia, to a 188-month prison  term, the minimum prescribed under the applicable sentencing  guidelines.


3
Appellant first contends that he did not know that the  scheduled airline flight from Colombia to Spain, where he was to  have delivered the cocaine, would land in Puerto Rico en route. See Fed. R. Crim. P. 11(c)(1) (mandating that district court inform  defendant of "the nature of the charge to which the [guilty] plea  is offered").  Although the Rule 11 colloquy conducted below in no  sense foreclosed it, the present contention inevitably fails since  it misapprehends the controlling law.  See, e.g., United States v. McKenzie, 818 F.2d 115, 118-19 (1st Cir. 1987) (upholding  conviction under § 841(a)(1) notwithstanding utter absence of  evidence defendant intended to distribute drugs within United  States).


4
Second, the district court's failure to address appellant  directly during important portions of the Rule 11 proceeding,  though contrary to Rule 11(c), violated no "core" Rule 11 concern  under our jurisprudence.2  See Allard, 926 F.2d at 1244-45; see also Cotal-Crespo, 47 F.3d at 4-5; cf. United States v. Medina-Silverio, 30 F.3d 1, 3 (1st Cir. 1994).


5
Third, appellant points out that the district court  failed to inform him that the mandatory minimum prison term prescribed by statute is ten years.  See 21 U.S.C. § 841(a) &  (b)(1)(A); see also Fed. R. Crim. P. 11(c)(1).  Furthermore, the  plea agreement itself misstated the minimum prison term as five  years, rather than ten.  Nonetheless, since it is undisputed that  the 188-month prison term imposed by the district court is the minimum required under the applicable sentencing guidelines, these  errors too must be deemed "harmless."  See United States v. McDonald, 121 F.3d 7, 11 (1st Cir. 1997) (holding "harmless" the  district court's failure to inform defendant of mandatory minimum  sentence, as court ultimately imposed sentence lengthier than  mandatory statutory minimum, "without any reference to the  mandatory minimum").


6
Finally, before accepting the guilty plea, the district  court did not address appellant directly in explaining the  constitutional rights to remain silent and confront adverse  witnesses at any trial.  See Fed. R. Crim. P. 11(c)(3).  The  government responds that the omission was harmless because  appellant signed the plea agreementitself, which accurately  reflected the charges, as well as the basic constitutional rights  waived under the plea agreement.3


7
In the "Statement of Facts" section of his appellate  brief, appellant offers the conclusory observation that the  district court violated Rule 11 in failing to advise that he would  have the right to confront adverse witnesses and to refrain from  testifying at any trial.  Then, at the very outset of the  "Argument" section in his appellate brief, appellant explicitly  delimits his argumentation to but two issues:  the alleged  violation of Rule 11(c)(1) by the district court, in failing to  inform appellant of (i) the nature of the charges to which he was  pleading guilty, and (ii) the correct mandatory minimum sentence, see supra.  Moreover, appellant neither presents developed  argumentation nor provides pertinent case citations respecting the  asserted Rule 11(c)(3) omissions.  Consequently, we deem these  embryonic claims to have been waived on appeal.  See, e.g., United  States v. Rosario-Peralta, 199 F.3d 552, 563 n.4 (1st Cir. 1999)  (appellate court deems waived issues presented in perfunctory  manner, without developed argumentation).


8
The present waiver is particularly conspicuous, in that  appellant neither suggests nor contends that he was actually unaware of these two constitutional rights at the Rule 11 hearing. Rather, upon being asked by the district court whether he had  "discussed with [his] attorney the meaning of pleading guilty," and  whether he was "satisfied with [his] attorney's representation,"  defendant responded in the affirmative, without limitation or  qualification.  (Emphasis added.)  Finally, our independent  research reveals that the caselaw -- concerning whether and in what  circumstances a Rule 11(c)(3) omission may constitute reversible  error -- is at best opaque,4 sufficient reason in itself to decline  to reach an important question upon which appellant provides no  elucidation whatsoever.


9
Accordingly, the district court judgment is affirmed.



Notes:


1
 See, e.g., United States v. McDonald, 121 F.3d 7 (1st Cir.  1997); United States v. Lopez-Pineda, 55 F.3d 693, 696 (1st Cir.  1995); United States v. Cotal-Crespo, 47 F.3d 1 (1st Cir. 1995); United States v. Medina-Silverio, 30 F.3d 1, 3 (1st Cir. 1994); United States v. Allard, 926 F.2d 1237 (1st Cir. 1991).


2
 See Cotal-Crespo, 47 F.3d at 4 (identifying "core concerns"  as absence of coercion, understanding of charges, and knowledge of  consequences of guilty plea).  There is no suggestion of coercion. See also n.1 supra.


3
 Contrary to the government's characterization, however, the  three-page plea agreement makes no mention of the two  constitutional rights addressed here.


4
 Compare, e.g., United States v. Tursi, 576 F.2d 396, 399 (1st  Cir. 1978) (finding no reversible error in district court's failure  to inform defendant of trial rights, but under pre-1976 version of  Rule 11, which -- unlike current Rule 11(c)(3) -- did not enumerate  specific trial rights), and United States v. Stead, 746 F.2d 355,  356-57 (6th Cir. 1984) (declining to vacate guilty plea though  district court admittedly failed to warn defendant of right against  self-incrimination and right to confront witnesses), with United  States v. Carter, 619 F.2d 293, 295 (2d Cir. 1980) (reversing where  district court omitted "core" requirement that defendant be advised  of confrontation rights).


