83 



throw off tlie old skin and the males form a cocoon oi' waxv fila- 

 ments which they secrete. This cocoon is an oblong cvlindrical 

 affair, six or seven hundreths of an inch long, in which the insect 

 remains for some time. There seems to be two sorts of males, one 



)f which tigure (I'i, comes from 

 the cocoon earlier than the other 

 form. As the figure shows, it has 

 very slighlK developed wings, so 

 small that they can be of no use 

 to the insect. This form seems to 

 be sexuallv perfect; although this 

 point is not certainly established. 

 They certainly pair witii the fe- 

 males, and jjrobablv impregnate 

 them. The bod}- of these males 

 arc about six hundreths of an inch 

 long and fifteen thousanths of an 

 inch broad. The true males fig- 

 ure t;.'5, middle figure, are fur- 

 nished with a pair of large wings 

 As has been indicated above, they 

 are longer in the process of pupation than the less fully winged 

 males coming from the cocoons some days later than the\' do. 

 The different form of the body, its more slender siiape, and espec- 

 ially the two long filaments extending from tiie abdomen of the 

 perfect males will be readily seen in the figure. It does not appear 

 clear whether the two classes of males develop from different 

 sorts of eggs or whether the ]')erfect males are those in which ad- 

 ditional development and moulting has occurred. Air. Howard 

 evidently thinks the latter to be the true explanation ol" the case. 

 "Judging from mv own observations I think it probable that some 

 differences in the food, season, climate, etc., atlecl the develop- 

 ment of the insects and that under some conditions impertl'ct males 

 predominate, while under others the perfect ones are more abund- 

 ant. In Europe it would appear that either the perfect males are 

 very scarce or have been o\erIook(;<l b\ entomologists, if we mav 

 judge from their writings. 



As figure 6;5 a. shows, the female l)elore pairing is very unlike 

 the other forms, and her own changes greatl\ after impregnation. 

 She is at first a spinv oval, wingless insect the segments ol the 



Figure 62. 



Gossyparia ulmi. 

 Imperfect male. 

 by which thev fl\- readilv 



