1920.J 203 



SOME EECORDS OF PREDACEOUS CERATOPOGONINAE (DIPTERA). 

 BY r. W. EDWAHDS, B.A., F.E.S. 



It has long been known that many of the species of the old genus 

 Cerafopor/071 are prcdaceous on other insects. Staeger (1838) states 

 that the females of all of them are predaceous, a statement whieli is far 

 too sweeping, but shows that he must have made many observations 

 on the point. Walker (1850), more cautiously, says that "the species 

 whose femora are armed with spines make a prey of other small insects, 

 which they pierce with their sharp proboscis." This remark, as will be 

 shown below, errs rather on the side of moderation, as some species 

 with unarmed femora are habitual predators. 



In spite of this long-known propensity of these insects, it is a 

 remarkable fact that practically no exact observations on the subject 

 seem to have been placed on record. Many observers have devoted their 

 attention to the prey of Asilidae and Empididae. but the almost equally 

 interesting Geratopngoninae have been ignored ; the only record I have 

 been able to trace being that of Malloch, who says (Bull. Illinois State 

 Lab. Nat. Hist, x, 1914, p. 216) that he has observed in Britain a lai'ge 

 species of Palpomyia feeding on a Perlid. There is also the case, dealt 

 with below, of Joliannsenomyia nitida feeding on its own male. 



I propose now to record a few observations of my own on this 

 subject, and hope that others may thereby be induced to pay attention 

 to the matter. In almost all the cases recorded the insects were found 

 on the roof of the "cottage" tent in which I usually sleep on my 

 summer holidays, in the evening or early morning. The tent, like an}"" 

 other raised object, serves to provide a place for male Chiroiiomidac to 

 swarm, and in nearly all cases the prey consisted of members of these 

 swarms, the predators being always females of bare-winged Ceratopo- 

 goiiiiiae belonging to various genera. The prey was seized in the air, 

 and together with its captor fell on to the tent roof, where the pair 

 were boxed. The preference of the Ceratopogoninae for males of other 

 Chironomidae, which this method of collecting indicates, may not 

 actually be so marked as appears, since otlier insects do not so readily 

 swarm over the tent ; I think, however, that it will be found to be the 

 general rule. Although I have not experimented in this direction, it 

 would seem very probable that much information on this subject could 

 be obtained by throwing a white sheet over suitable low bushes above 

 which Chironomids are swarming, and observing the insects which fall 

 or settle on it. 



