342 THE GYPSY MOTH. 



the fore wings, when closed, rests on the side of the thorax. 

 A similar organ occurs in Ocnei^ia rubea of Europe, of the 

 same structure and in the same place as in the gypsj moth. 



The scales on the wings vary in form, as shown in Plate 

 52, Figs. 10-20. The striations are not shown in all these 

 figures. Fig. 15 represents one of the short and broad 

 scales with the longitudinal strife. Figs. 21 and 22 repre- 

 sent cross-sections of a scale, the first from near the base, 

 the second from the broader part of the scale. After suitable 

 preparation and embedding inparaffiue, a portion of the wing 

 was sectioned and these figures drawn from the mounted 

 sections. The surface of the scale next the membrane of 

 the wing is smooth, while the outer surface is covered with 

 loDo-itudinal ridges. 



The abdomen of the female (Plate 51, Fig. 1) is very 

 large, and densely clothed with yellowish hairs, especially 

 on the under side towards the posterior part. One of these 

 hairs is represented in Plate 52, Fig. 19, and a section of 

 it, near the basal fourth of the hair, greatly enlarged at 

 Fig. 10. The surface is covered with minute spines, which 

 incline towards the apex, and it also appears to be marked 

 with irregular cross-wrinkles. The ovipositor of the female 

 is shown in Plate 51, Fig. 2. 



Mating. 



After emerging the female crawls a short distance from 

 the pupa-case, and, by the time the wings have expanded, 

 and sometimes before, she begins to attract or "assemble " 

 the imagoes of the opposite sex. In colonies where the 

 males are abundant, they often attempt to mate with females 

 almost as soon as the latter emerge. Seeking the female, the 

 male flies in a zigzag course until she is found, when he 

 hovers around her for a few minutes, rapidly vibrating his 

 wings. 



The time spent in mating has been found to vary from 

 twenty-five minutes to three hours and eighteen minutes ; 

 the average time of twenty-four pairs being one hour and 

 nine minutes. Alter mating, the male is quite stupid, but 

 in about half an hour regains his normal activity. 



