REPORT OF THE STATE ENTOMOLOGIST I907 21 5 



flies (Hydroptilidae) and a few larger caddis flies of the genus 

 Hydropsyche. 



Males are more in evidence, but probably not more abundant 

 in fact. The females come out from their resting places only 

 to lay their eggs, and are only to be seen when busily engaged 

 in the performance of this task. They stand on tiptoe, with 

 the long ovipositor held in vertical position at the tip of the 

 deflexed abdomen, and they swing the body up and down in 

 rapid shuttlelike vibration, freely rising and falling on the long 

 and widely outspread legs. Thus the point of the ovipositor 

 is driven against the wet surface of the plank, thrusting almost 

 as rapidly as the needlebar of a sewing machine: it is moved 

 about over the surface, as if searching for soft spots in the 

 wood, and occasionally it makes a deeper thrust when a suitable 

 place is found, and an egg is deposited. 



The egg-laying process is often interrupted and is continu- 

 ally interfered with by the too importunate males. When a 

 male in running about on the plank comes upon a female 

 ovipositing, he stands directly above her at the full upward 

 stretch of his legs, while she goes right along with her work; 

 but the instant she ceases her vibrating and lifts her ovipositor, 

 he is ready with his forceps, upturned and outspread at the 

 tip of his decurved abdomen, to seize her. Usually she does 

 not want to be interrupted and moves away, while he tries to 

 run parallel and maintain all the while his position of vantage 

 above her. Often other males are encountered, and then the 

 males engage in a rough and tumble fight. They push and 

 shove each other in a most ludicrous manner, reminding one 

 of pigs fighting, and often an encounter of this sort enables 

 the female to escape and to go on quietly with her work. 



The males have well developed eyes, but their sight must be very 

 poor ; for, while always searching for females, they seem quite 

 unable to find them by sight, often passing females at work within 

 a distance of a few centimeters. But their tactile sense seems 

 more acute. When a male in running to and fro had passed several 

 times within 6 centimeters of a female without noticing her, was 

 deflected from his course toward her by an obstruction I purposely 

 placed in his way, he instantly sprang toward her upon the slightest 

 contact, even of tips of tarsi, but was quite unheeding until this 

 contact occurred. If it did not occur he would pass on, even by 

 the narrowest margin. 



