1909]. 159 



clasped round the strui^glinG; victim. He then proceeds to feel with 

 the tip of the proboscis over the thorax of the fly, finally reaching 

 and immediately piercing the junction between head and thorax. The 

 proboscis was withdrawn after a few seconds, the victim being appar- 

 ently paralyzed and only showing slight movements of the body or 

 limbs. Several males were boxed directly after they had begun to 

 hang by one leg. Tn'all such cases the in:endcd victim was quite 

 uninjured, l)oth Empid and fly being equally lively. These observa- 

 tions seem to point to the conclusion that it is the central nervous 

 system that is acted upon, and an effect produced similar to that 

 wrought by the sting of a fossorial wasp upon its prey. Additional 

 support is also lent to this view by the perfect and u linjured 

 condition of the victims held by the males. In the very large number 

 captured and examined no trace of any puncture of thorax or other 

 part could be detected. Thisspecies like opaca confines its attention 

 exclusively to Diptera. 



E. trigramma, .Mg - J thought ..t one time that all the species in 

 this genus might exhibit habits similar to those already recorded. 

 Careful observation, has, however, proved that E. tri(]rammn at all 

 events is an exception ; lor the prey captured by this species is 

 devoured independently of copulation. The male and female tri- 

 cjramma without prey go through a rather elaborate form of courtshij) 

 prior to pairing — most interesting to watch, but difiicult to describe — 

 the following observations wcsre made during May and June, at Lye 

 Hill. On June 5th at 6.4s p.m., I was looking at a female tricjramma 

 resting on an alder leaf, when a male alighted about an inch distant 

 from her, fluttered his wings for a few seconds, then raised his 

 anterior legs and waved them about. The female then fluttered her 

 wings and raised her anterior legs and moved them about also, 

 apparently in response. The male then rubbed the anterior tarsi 

 together for some seconds moving them quickly and at the same time 

 rapidly vibrating his wings, which were maintained in a horizontal 

 position. These actions were repeated with variations by one or the 

 other for the space of three minutes. The pfiir had now drawn closer 

 so that each was able to touch the other's anterior tarsi in a caressing 

 manner. This they continually did, the male every now and then 

 rapidly vibrating his wings. These actions continued for over two 

 minutes, when the female slightly raised the apex of her abdomen, 

 the male gently flew on to her back, and pairing took place 

 immediately. The total time occupied in courtship was, therefore, 

 about five-and-a-half minutes. The leaf with, the pair in copula was 



