inse;cutor insciti^ mknstruus 63 



THE OVIPOSITION OF JOBLOTIA DIGITATUS . 

 RONDANI 



(Dipt era, Culicidce) 

 By J. LENNOX PAW AN 



Johlotia digit atus Rond. commonly deposits its egg in the 

 rain water that accumulates in the broken cocoa pods strewn 

 in heaps on the ground about the cool, shady parts of cocoa 

 fields, in Trinidad, B. W. I. 



The "parturient" female assumes a characteristic attitude 

 upon the surface of the water. Her hind pair of legs lie 

 extended backward to their maximum length and slightly out- 

 ward. The front pair of legs are projected forward and out- 

 ward, the femur forming almost a right angle with the tibia 

 and the latter an obtuse angle with the tarsus which rests 

 forward and outward. In both the front and hind legs the 

 tarsi are the only parts in direct contact with the surface of the 

 water. The position of the middle pair of legs is very definite ; 

 the femur is directed backward, the tibia is acutely flexed for- 

 ward and the ankle joint embraces firmly the lateral borders of 

 the egg mass, the tarsus projecting sharply backward and rest- 

 ing upon the surface of the water. The thorax, abdomen and 

 head are raised above the water. While the cohesiveness of 

 the egg mass is maintained through the clasp of her middle 

 ankle joints, the weight and buoyancy of the eggs preserve her 

 from being submerged during the process of oviposition. This 

 process, which usually takes place in the morning, lasts from 

 two to four hours, during which time she seems quite helpless, 

 being unable and unwilling to take to her wings if disturbed, 

 lendering herself an easy captive and giving one the impression 

 of being in pain. After oviposition has ceased she continues to 

 rest upon the surface of the water, often away from the egg 

 mass for from two to three hours, then crawls to the sides of 

 the containing receptacle and gladly wings a rapid flight away. 



The eggs lie in circular or square-like masses, consisting of 

 from 25 to 40 in number, floatir/g with their long axes perpen- 

 dicular to the surface of the water and glued together at their 



