422 Transactions of the Society. 



antennae of the female are unusually numerous and well developed 

 — far more so than in those of the male. 



The " scent pits " on the antenna? of many of the Ichneumonidae 

 are very large and regularly disposed on each of the numerous 

 joints. Mr. C. 0. Waterhouse, Pres.E.S., told me that he has watched 

 the females of certain species using the antennas to detect the 

 presence of larvae living under the bark of the smaller branches of 

 shrubs ; this was obviously done by scent, and when the insect 

 was satisfied of the presence of its prey the ovipositor was brought 

 into play and eggs laid in or near the unfortunate host. It is well 

 known that the larvae of the Tachinidae in which family Pkorocera 

 is placed, live on the larvae of other orders, and even on the larvae 

 of a species of fly (Sciara mali Fitch). It therefore appears pro- 

 bable that the host of P. serriventris is some insect that burrows 

 into wood or other substance, and the ovipositor and the highly 

 specialised scent-organs (dependent on each other for successful 



Fig. 116. Fig. 117. Fig. 118. 



Fig. 116. — Receptaculurn semiuis of Conops flavipes L. Four are found in this 

 insect ; actual size, circa 200 /j.. 



Fig. 117. — Receptaculurn of Chrysopillus aureus Mg. Three are present in this 

 insect ; actual size, 130 p. 



Fig. 118. — Receptaculurn of Beris vallata Forst. Three are found in this insect, 

 and each have the long tubular attachment figured ; these organs in the Tabanidae 

 and Asilidse have similar appendages. Actual size of bulb, 100 /*. 



application) have developed, giving Phorocera particular advantages, 

 possibly the monopoly of a species, for the food of its larvae. 



These flies were quite common in a garden in South Hamp- 

 stead in the month of June. 



6. The pupa will be found in the abdomen of the Hippoboscidae, 

 those remarkable flies which have been so modified that they pass 

 through the larval stage in the abdomen ; it is but seldom that a 

 specimen shows this. 



7. The receptacula seminis may be regarded as part of the 

 female genitalia, but for convenience I will make what few remarks 

 I have to make here. I am only acquainted with these organs in 

 Diptera. They vary remarkably and inexplicably, not only in 

 number (from one to four) but in sculpturing and shape, species 

 differing from species. In groups like the Anthomyidae, where 



