FS\CHE. 



831 



ON THE GENUS THLIPSOGASTER ROND. 



BY S. W. WILLISTON, LAWRENCE, MASS. 



In the Transactions of the American 

 Entomological Society for March, 1895, 

 p. 108, Mr. Coquillett referred to this 

 genus of Rondani two American species, 

 T. ater Coq. which I have before me 

 from Mexico, and T. syndesmus Coq., 

 which I have seen from Kansas. A 

 careful examination of the literature 

 assures me, however, that there is no 

 real relationship between our species 

 and the types of Thlipsogaster. Whether 

 or not the species described by Mr. 

 Coquillett and several other allied ones 

 known to me should receive a new gen- 

 eric name is a question that I will leave 

 in abeyance. The only real difference 

 from Bombylius which they present is 

 in the first posterior cell of the wings 

 being closed in the margin instead of at 

 some distance from it. Apparently ad- 

 ditional characters are found in the 

 peculiar markings of all the known 

 species ; all of them, for instance, pos- 

 sessing a silvery spot near each eye at 

 the base of the antennae. Were these 

 characters confined to such species as 

 present the neurational character, I 

 should not hesitate to give the genus an- 

 other name. Unfortunately, however, 

 such species as Bombylius lugubris Loew, 

 and B. ater Lin., especially the latter, 

 seem to have very similar markings, 

 though the first posterior cell is closed 

 remotely from the margin. As T. ater 



Coq. must be retained in the genus 

 Bombylius for the present, at any rate, 

 the specific name Coquilletti may be 

 substituted in order not to conflict with 

 B. ater Linn. 



My reasons for rejecting Thlipso- 

 gaster Rond. for these species are as 

 follows : 



Thlipsogaster Rond. was separated 

 from Thlipsomyza Wiedemann in a very 

 imperfect way as follows : " Al genero 

 fondata dal Wiedman per una specie 

 Affricana furono aggiunte altre due 

 parimenti dall' Affrica dal Macquart, 

 ma diversi caratteri di queste non com- 

 binano con quelli della prima, per man- 

 iera che si rende necessaria la loro 

 separazione almeno in due generi." 



" AA. Alarum areolae submargin- 



ales duae tantum. * * 



BB. Venae longitudinales alae 

 quinta et sexta [tertia et 

 quarta] sejunctim marginem 

 alae attingentes vel vix in ipso 

 contiguae. 

 G. Thlypsogaster Mihi. 



Cont. Sp. Castanea et Heter- 



optera Macq." * 



In all probability Rondani had not 



seen these species when he erected 



the genus, but took the characters 



from Macquart. Turning to Macquart t 



* Arch, per la Zool. 1S63, p. 72. 

 tDipt. Exot. ii, 1,32 and 113. 



