1908] COCKERELL — BEE-GENUS EXAERETE 41 



NOTES ON THE BEE-GENUS EXAERETE. 



BY T. D. A. COCKERELL, BOULDER, COLORADO. 



The parasitic or inquilinous genus Exaereie Hoffmannsegg (Chrymntheda Perty) 

 is placed by Ashmead and other authors in the vicinity of Melissa, Mesocheira etc., 

 these and many other genera forming a family Nomadidae. That these genera repre- 

 sent several different stocks, is recognized by Ashmead himself (Trans. Amer. Ent. 

 Soc, 1S99, p. 65), and of all the discordant elements assigned to the "Nomadidae," 

 the most discordant is Exaerete. The brilliantly colored bees of this genus were re- 

 ferred by Fabricius, Latreille, Lamarck, and other early authors to Eurjlossa, and 

 this I believe was more nearly correct than their present position in the midst of the 

 parasitic bees of Anthophorid stock. In structure and appearance they resemble 

 Euglossa, and especially the closely related genus Eufriesea,^ in which the pubescence 

 is rather scanty, the mouth parts are dark, and the scutellum has no patch of black 

 tomentum. It is also to be noted that they are parasitic in the nests of Euglossa and 

 its immediate allies (cf. Ducke, Zeits. f. wiss. Insektenbiol., 1906, p. 58.). It seems 

 evident that Exosrete is derived from the Euglossids, and is related to them as Psithyrus 

 is to Bombus. Ashmead makes a distinct family, Psithyridae, following Schmiedek- 

 necht; but it seems better to recognize only a subfamily, Psithyriiiae, ior Psithyrus, 

 and similarly to refer Exaerete to a subfamily Exaeretinae of the Euglossidae. 



The immediate occasion of these remarks was a specimen of Exaerete dentata (L.) , 

 received from the Museum of Comparative Zoology; the first member of the genus 

 I had ever had occasion to study. I refer it to the Linnean dentata, but I find no really 

 adequate description of that species, and it is not impossible that there are several 

 forms in the great Amazonian region which would equally fit the Linnean diagnosis. 

 The following particulars regarding the specimen before me may therefore be useful. 



Exaerete dentata (!>.) 



?. Length (the head somewhat extended) about 17^ mm.; entirely bright 

 green, with strong purple tints on thorax and abdomen in certain lights, the color 

 exactly like that of Euglossa eordata toumsendi Ckll. ; wings exceedingly dark fuligi- 

 nous ; mandibles and labrum without light marks ; cheeks with short scanty white 



^Eufricsea n. n. = Eumorpha Friese, Termes Fuzetek, 1899, p. 126 (not Hubner, 1806). Type 

 Eujriesea pulchra (^Euglossa pulchra Smith.). 



