458 



modified from the original cycle occurring on wild vines. The winter 

 is only passed in one form, the hibernating larva, which is found on 

 the roots and occasionally on the trunk beneath the bark. When 

 mature this form gives rise to generations of radicicolae, the Aphids 

 that issue from eggs in the autumn hibernating. Owing to various 

 influences, such as temperature, food, variety of vine, etc., some of 

 the radicicolae develop into winged migrants and issue 'from the 

 ground. The root-feeding larvae also reach other vines by way of 

 the soil surface or subterranean cracks, etc. The injury caused to 

 vines and the methods of distributing the pests are discussed at length. 



Caffrey (D. J.). Biology and Economic Importance o£ Anastaius 

 semiflavidus, a recently described Egg Parasite of Hemileuca 

 oliviae. — Jl. Agric. Res., Washington, D.C., xxi, no. 6, 15th 

 June 1921, pp. 373-.384, 1 plate, 3 figs. 



Anastatus semiflavidus, Gah., appears to be one of the most efficient 

 natural enemies of Hemileuca oliviae in New Mexico. It has also 

 been found parasitising eggs of H. nevadensis. Stretch, on willow, 

 and this moth may prove a useful host for perpetuating the species. 

 Attempts to rear the parasite on eggs of Malacosoma fragilis, Stretch, 

 collected from scrub oak, were not successful. Under field conditions 

 oviposition occurs in the middle of September, as soon as the eggs of 

 the host have been deposited, and continues until the advent of severe 

 winter weather. It is thought probable that the earlier eggs hatch 

 and hibernation takes place as a partly developed larva within the 

 host, whereas those deposited later in the season overwinter in the 

 egg stage. The length of the larval period is uncertain, varying in 

 some observations from about seven months to two years. The 

 development of the pupal stage depends largely upon external climatic 

 conditions ; thus, should -a full-grown larva be subjected to a long 

 period of drought, pupation may be delayed, and a dormant larval 

 period of indefinite duration be produced, until both humidity and 

 temperature are favourable for further development. After a very 

 short pupal period the adults emerge. Only one parasite develops 

 in each egg. Each female produces about 60 or more individuals. 

 Adults are found in the field from early May to early December, the 

 maximum emergence occurring in July and August. From one series 

 of observations the total life-cycle is estimated at an average of 380 

 days, with a minimum of 226 and a maximum of 449 days. 



Phillips (W. J.) & Poos (F. W.). Life-history Studies of three 

 Jointworm Parasites. — //. Agyic. Res., Washington, D.C., xxi, 

 no. 6, 15th June 1921, pp. 405-426, 6 plates, 16 figs. 



Ditropinotus aureoviridis , Crawf., and Homoporus chalcidiphagus, 

 Walsh & Riley, are primary parasites of Harmolita tritici, Fitch, 

 and have a similar distribution to the host. Eupelmus allynii, French, 

 is both a primary parasite and hyperparasite of the same host, and is 

 commonly found wherever the Hessian fly, Mayetiola (Phytophaga) 

 destructor. Say, and the majority of Harmolita spp. are found. 



The chief host of the Torymid, Ditropinotus aureoviridis, besides 

 H. tritici, is H.vaginicola, Doane, and it has been reared in cell slides 

 from H. elymicola, Phillips & Emery, and from field collections of 

 H. grandis, Riley, H. atlantica, Phillips & Emery, and H. sccalis. 

 Fitch. It also breeds freely on the larvae of Enrytoma spp. 



