109 



Miscellaneous Notes on Hymenoptera. 



With Descriptions of Xew Genera and Species. 



BY JOHN COLBURX BRIDWELL. 



1. Hymenoptekous Lakvae wiTit Falcate Mandibles. 



]\[r. C. E. Pembertou in his recent work on the life-histor- 

 ies of the fruit fly parasites has found that the Opiine Braco- 

 nids and the Diapriid Galesus Silvestrii have the first larval 

 stage provided with long falcate mandibles which are used to 

 destroy other larvae in the same host. He has also in unpub- 

 lished studies on the life-history of the parasite of the Lan- 

 tana Agromyzid described in another paper in this issue as 

 Opius lantanae found the same type of first stage larva. Oglo- 

 bin found the same type of larva in the Coccinellid Braconid 

 Dinacampus terminatus (JSTees). I have found the same type 

 in the Bruchid parasite HeterospiJus prosopidis Crawford and 

 Graenicher has found a similar larva in some of the parasitic 

 bees. 



On the other hand Pembertou and Willard in studies of 

 the external parasite of lepidopterous larvae here described as 

 Micvohracon Pembertoni have found an entirely different type 

 of first instar larva. The first stage larva of Aphycus. Peri- 

 lampus, Tetrasticlius. ScuteUista, and many other Chalcidoid 

 parasites are very different. 



What then is the significance of the falcate mandibles ? 

 Are they phylogenetic in significance or adaptive '^ The latter 

 seems to be the case and we may perhaps safely generalize in 

 this way. Cetain species of parasitic Hymenoptera where the 

 prey or host is concealed and successive parasitization is prob- 

 able have independently developed the long falcate mandibles 

 which give a means for one larva to destroy the other At 

 any rate in the cases studied one larva alone reaches maturity 

 and in the case of some at least in which the mandibles are 

 not so developed more than one parasite can reach maturity 

 upon a single host. 



Proc. Haw. Ent. Soc, IV, No. i, June, 1919. 



