31 



general color is black, with yellow mouth-parts and legs. The 

 wings are transparent and beautifully iridescent under the magni- 

 fying glass. The male closely resembles the female, but has two 

 more articles in each of its antennse and has the tip of its abdomen 

 blunt instead of sharp pointed. The following more detailed des- 

 cription will serve to distinguish the species from those which in- 

 fest other plant lice. 



Adialytas maidaphidis, nov. sp. Head and thorax black, shining, 

 smooth. Abdomen reddish brown, darkest on the middle of the 

 segments, with a few short whitish hairs. Front with whitish hairs. 

 AntenniTB dull black. Mouth-parts pale honey yellow. Coxae of an- 

 terior and middle legs, trochanters of all the legs, anterior and 

 middle femora, anterior tibiiB and tips of middle and hind tibiae 

 honey-yellow. Posterior femora mostly black. Limbs clothed with 

 appressed silky white pubescence, thickest on the tibite and tarsi. 

 Hind coxffi black. Tarsi dusky. Wings transparent, iridescent, with 

 some yellow at base and a basal half of costa. Stigma smoky 

 brown, with a touch of yellow at its inner angle. Nerves black. 

 Head subspherical. Eyes large and prominent. Three ocelli 

 conspicuous. Antennae of 13 articles in the female ; with 15 

 in the male. Two proximal articles equal in length, shorter 

 than the others, about as long as wide. The succeeding articles 

 about equal in length, about twice as long as wide. Distal article 

 in female longer than the others ; in the male it is about equal to 

 them. The articles are longitudinally, finely carinate. Thorax ob- 

 ovate, elevated anteriorly, impunctured. Abdomen spindle shaped, 

 depressed, pointed in the female, blunt in the male. Legs long and 

 slender ; femora spindle-shaped, about three-fourths the length of 

 the tibiffi. TibiiB slender at base, gradually enlarging to their ex- 

 tremities. First article of tarsi long and uniform in diameter ; about 

 as long as the three succeeding together. Second article a little 

 larger than the following ones and slightly swollen. Three distal 

 articles subequal. Length, 2 mm. 



During the summer and autumn these little flies may be seen 

 running rapidly about on the corn which is infested with lice, and 

 if watched will be seen now and then to approach a plant louse, 

 tap it gently with the antennae, and if the louse seems to be satis- 

 factory, the abdomen of the parasite is suddenly bent downwards 

 and then forwards between the legs, the victim is stabbed by the 

 short, sharp pointed ovipositor and an egg is inserted at the same 

 time in its body. The parasitized louse continues to feed after the 

 egg has been deposited as if nothing had occurred to discommode 

 it, and if young may continue to grow until the natural size is 

 reached. All this time the great grub hatched from the egg is 

 feeding upon its tissues and growing rapidly so that by the time it 

 gets its growth the body of its host is swollen out greatly beyond 

 the usual proportions. The grub seems to avoid the vital organs 

 of its host until the last so that the louse does not entirely succumb 

 until the grub is ready to become a pupa, at which time it seems 

 to devour all the remaining tissues or crowd them aside to make 

 room for itself. The body of the louse has by this time become 

 brown and dry, and though outwardly looking like a very plump 

 plant louse is really only a skin enclosing a parasite. By some 

 means, not ascertained, the swollen body becomes glued^ to the leaves 



