PSVCHE. 



NOTES ON THE LARVAE OF SOME TEXAN DIPTERA* 



BY CHARLES THOMAS BRUES, AUSTIN, TEX. 



During the past winter I obtained the 

 light yellow silken nest of a spider, which 

 instead of the usual quota of eggs or 

 young spiders, contained a mass of small 

 yellow hymenopterous cocoons and a 

 number of white grubs of various sizes 

 which I supposed to be the larvae of the 

 hymenopteron. Some of the latter soon 

 pupated however, and later emerged, 

 when they proved to belong to a species 

 of the dipteron genus F/iora, which seems 

 to be undescribed. From the hymenop- 

 terous cocoons appeared specimens of 

 Pimp/a aiiniilipes BruUe'.t Some young 

 spiders from a similar nest were kindly 

 identified by Mr. Nathan Banks as be- 

 longing to the genus Epeira. 



So far as I can ascertain no other 

 species of Phora is known to be parasitic 

 on spiders eggs. Some species live upon 

 dead insects or snails, others in decaying 

 vegetable matter, while a few are internal 



* Contributions from the Zoological Laboratory of tlie 

 University of Texas. No. 29. 



t Spiders' eggs seem to be the customary hosts of the va- 

 rious species of /*/;«//«. Howard, in an interesting paper 

 on the hymenopterous parasites of spiders (Proc. Ent. Soc. 

 of Washington, Vol. II, No. 3, p. 290) mentions three other 

 American species of Pimpla which infest the cocoons of 

 Epeirid spiders. 



parasites of other insects, t There can be 

 no doubt that the Phoras were primaiy 

 parasites of the spiders eggs and not 

 secondary ones living in the Pimpla 

 larvae, as the Phora larvae of all sizes 

 were free, the smaller ones evidently fail- 

 ing to mature from lack of food, only two 

 spider eggs remaining from the whole 

 nestful. This is thus not a case of true 

 parasitism accompanied by degeneration, 

 but a condition where a predatory in- 

 stinct and a considerable power defence 

 must be possessed by the larva to enable 

 it successfully to live and develop in the 

 midst of a nest full of young spiders, 

 voracious often to cannibalism. 



The following is the description of the 

 new species of Phora. 



Phora epeirae, sp. nov. 



Length, 3-35 mm. Rather broad and 

 stout, almost wholly vellow. Abdomen quad- 

 rimaculate. Face shining, delicately ptinctii- 

 late, witli a lateral row of four bristles : the 

 vertex with four biistles, arransjed at the 



+ For a complete list of the European species with their 

 food-habits see Brauer, Systematisclie .Studien der Diptern- 

 Larven. Denkschriften der mathematisch-naturwissen- 

 schaftlichen Classe der k. .Akademie der Wissenschaften 

 Wien. Bd. 47 p. 66. 1883. 



