264 MAINE AGRICULTURAI, EXPERIM^KT STATION. I914. 



may, perhaps, belong to distinct generations, though they are 

 both present at the same time. 



The alate viviparous form has a s'hiny black head and tho- 

 rax and a pale green abdomen decorated with lateral black 

 dots, a large dusky spot on the dorsum, black cauda, cornicles, 

 and ventral patch and dashes of black on ventral abdominal 

 segments 4, 5 and 6. The beak extends to or in some cases 

 well beyond the third coxa. The wings are not particularly 

 •distinctive but are characterized by a short stigma in the fore 

 wing and the curve in the hind wing sufficient to render the 

 proximal part rather slender. The antenna has 30 more or 

 less sensoria irregular in size and irregularly placed along III, 

 and IV without sensoria; V is shorter than IV and the spur of 

 VI about the length of III. The cornicle is cylindrical and 

 its length in relation to antennal III is shown in the figure. 



This species inhabits the new growth twig and ventral sur- 

 face of terminal leaves causing curl. 



Maine collection numbers 16-04; 17-04; 17-06; 18-06; 123-06; 

 7-09; 25-10; 50-12; 73-12; 169-12 in part. 



Aphis avenae and Aphis hrevis. Fall migrants of these spe- 

 cies I have taken together on cultivated plum (169-12), but 

 these have received fuller treatment elsewhere. 



Phorodon humuu. The Aphid of Plum and Hop. 



(Figure 89, A-B. Figure 95, H.) 

 This is a serious pest on both its food plants in certain 

 parts of the country. As the hop is only incidental in Maine 

 we do not often get complaints of this plant louse on its sum- 

 mer host. It is sometimes injuriously abundant on plum, 

 causing leaf curl. This is not a mealy species. 



The apterous forms are very pale green with a median and 

 lateral lines of darker green, — giving three rather conspicuous 

 longitudinal dorsal stripes. The dorsum of the winged form 

 is decorated with black markings and there are lateral black 

 spots. The antennae are shown in Fig. 89. The projection 

 •of the head at base of the antenna is the conspicuous distinc- 

 tive feature of this aphid both in the winged and wingless 

 forms. Maine collection numbers 70-12 on plum, 77-12 on 

 "hop. 



