GYNANDROMORPHS IN HABROBRACON. IOI 



While some variation obtains in size of sternites, those of 

 the male are much smaller than corresponding sternites of the 

 female. External genital ia of the male bear no resemblance to 

 sting and sensory gonapophyses of the female (Figs. 9-15). 



Mating reactions of the male begin with flipping of the wings 

 and running about excitedly when in the presence of the female 

 or if set where a female has recently been. In small vials a 

 male, apparently much excited, may often pass close by a female 

 without noticing her. If, however, his antennae come in contact 

 with her he will mount and attempt to mate. Copulation is 

 accompanied by a rhythmic beating of wings and antennae. It 

 may last from three or four seconds to two minutes and may be 

 repeated without dismounting. A male may mate several times 

 in close succession especially if new females are introduced. 

 Males show much individual difference in vigor of mating 

 reactions. The same male may show no reaction at one time 

 and a very vigorous reaction later. Females differ in their 

 capacity to stimulate the response. A male may be -stimulated 

 by another male and even mount him but the response is much 

 more pronounced toward a female. A female may remain quiet 

 and permit mating, or give a negative response by running away. 

 If the male persists she kicks him off and bends the tip of her 

 abdomen downward and forward in order to avoid him. He 

 may accomplish a mating in spite of this resistance. A male 

 which is mounted by another male acts in a way somewhat 

 similar but since the aggressor in this case soon desists the nega- 

 tive response is not so pronounced. A female may rarely flip her 

 wings a few times when first introduced to a male. It may be 

 questioned whether this is a sex reaction or a response of a more 

 general type. 



Injury to antennae of males interferes with normal mating 

 reactions. If ether fumes have been too strong there may be an 

 inability to sense the odors from the female. If contact between 

 antennae of the male and body of the female occurs there may 

 nevertheless be a vigorous response. Antennae thus injured by 

 ether fragment after two or three days and terminal portions 

 drop off. 



Males are entirely indifferent to caterpillars, running over 



