Pomona College Journal of Entomology 595 



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'Male — Length .()!• inch. Color brown and brown-black; antennse brown, 

 legs pale or yellowish, posterior femora slightly shaded above with brown or black; 

 feet reddish; nectaries shorter than in female; wings hyaline, stigmal spot pale. 

 These are rare among the first broods, and afterwards almost or entirely disappear. 



" 'Female — Apterous, length 0.05 to 0.06 inch. Broadly ovate. Dark brown- 

 ish-black. Head between antennae reddish: antennae seven- jointed, pale yellowish, 

 apical ends of joints, three, four and five brown, six shortest, seven long, setaceous; 

 legs pale yellow, latter two-thirdg of the femora brownish or blackish, tips of tibiae 

 and claws brown ; nectaries slightly thickest at base, black and cylindrical, cauda 

 distinct. 



"'Winged Viviparous Female — Length l.Ot) inch. Color black and shining; 

 eyes red-brown, tubercles of antenna- black, vertex of head reddish; rostrum reach- 

 ing back of middle coxse; antennae not quite reaching to tip of abdomen; abdomen 

 \ariable, brown-black, brown or olive-green ; wings hyaline ; stigma rather broad, 

 brown, obliquely sharpened to a point at outer edge towards apex ; stigmal vein 

 strongly curved, dark ; three oblique veins, the third forked ; hind wings with two 

 oblique veins in all specimens but one, nectaries long, cylindrical and black; cauda 

 long and recurved, dark. 



" 'I have watched these viviparous females breed on my orange trees and the 

 rapidity with which this is done is simply astonishing. In a few days broods upon 

 broods, or young colonies, seem to exist on all the tender new leaves and shoots, 

 and still the parthenogenetic young keep coming. Verily, if it were not for the 

 chalcid flies, ichneumons and other parasites, they would be the death of the trees. 

 By the middle of !March a change takes place in the broods. The young differ from 

 their parents in shape, color and size. So different are they as to discredit belief, 

 .and had I not watched them breeding day by day on my orange trees, I should have 

 felt justified in describing them as a distinct species. They are undoubtedly a 

 dimorphic form, and I give below a description: 



" 'Dimorphic, Viviparous, Apterous Female — Length, 0.08 to 0.09 inch. Elon- 

 gate; color of a uniform pale pea-green with more or less of a longitudinal shading 

 of darker green on tlie dorsum, with the surface more or less corrugated ; eyes 

 bright red, with a prominent facet or ocellus springing out from hinder edge of 

 same, giving it a tooth-like appearance; antennae VII jointed, pale glassy green, in 

 mature specimens the tip from the fifth joint is reddish; legs of the same uniform 

 pale green; cauda small, conical. Beak does not quite reach to tip of middle coxae.' 



"The winged form agrees in every respect with the above description, and 

 can only be distinguished by having wings, the veins of which are very pale. These 

 are rare, the majority being wingless. 



"The mature viviparous female continues breeding and can often be found 

 surrounded by from twenty- to thirty pale green young; occasionally a brown one 

 will be found among them. These continue breeding for several generations, ulti- 

 mately giving place to the original type, and by the last of April none can be found. 

 Why this change of form occurs is yet a mystery, and needs further investigation. 

 Towards the end all seem to be parasitized by a Trioxys, T. testaceipes Cresson, 



