OAK SCALE-INSECTS. 99 



other citrus j)lants, ou olive, pear, apricot, plum, pomegranate, Oregon 

 ash, bitter-sweet, apple, eucalyptus, sabal palm, California coffee, rose, 

 cape jessamine, Habrothmus elegans ; and elsewhere upon an Australian 

 plant known as Brachaion, and also upon a heath. It i^referably attacks 

 the Lsmaller twigs of these plants, and the young usually settle upon the 

 leaves. 



The development of this species is very slow, and it seems probable 

 that there is only one brood in a year. Specimens observed by Mr. 

 Alexander Craw at Los Angeles, which hatched in June or July, began 

 to show the characteristic ridges only in November. Mr. Craw has 

 seen the lice, even when quite well grown, move from twigs which had 

 become dry and take up their quarters ou fresh ones. 



Although carefully looked for, the males, like those of so many other 

 Lecanides, have never been found. 



A dark-brown bark-louse has been sent me from Florida, on live oak, 

 holly, oleander, orange, and one or two unknown plants, by Dr. R. S. 

 Turner, of Fort George, which appears to be identical with Lecanium 

 olece. It is, however, by no means as abundant or injurious in that 

 State as in California. 



Enormous quantities of the eggs of the black scales are destroyed by 

 the chalcid parasite Tomocera caUfornica,* described on p. 368 of this 

 report. Particulars as to the work of this parasite are given at the 

 same place. Upon one occasion (August 25, 1880), I found within the 

 body of a full-grown female a lepidopterous larva, which was very similar 

 in appearance to the larvae of the species of Dalcruma described in my 

 last report as destroying bark-lice. The specimen, however, was lost, 

 and no more have been found since. 



A number of beetles of the genus Latridius were found under scales 

 which had been punctured by the Tomocera, but probably would not 

 destroy the live insect. Many mites were found feeding upon the eggs 

 and young. The infested trees were also swarming with the different 

 species of lady-bugs {Coccinellidce). (Comstock.) 



Adult female. — Dark brown, nearly black in color; nearly hemispherical in form, 

 often, however, quite a little longer than broad; average length from 4'"™ to 5'"'"' 

 average height, I^"'''". Dorsum with a median longitudinal carina and two transverse 

 carinfB, the latter dividing the body into three subequal portions; frequently the 

 longitudinal ridge is more prominent between the transverse ridges than elsewhere, 

 thus forming with them a raised surface of the form of a capital H> The body is 

 slightly margined ; outer part of the disk with many (18 to 30) small ridges which 

 extend from the margin half-way up to center of dorsum. Viewed with the micro- 

 scope, the skin is seen to be filled with oval or round cells, each with a clear nucleus, 

 the average size of the cells being from .Oo™"! to .06""" in length, while the nuclei 

 average .02™™ in diameter. The antennae are long and 8-jointed, the two basal joints 

 short ; joint '^ longest, joints 4 and 5 equal and shorter, joints 6 and 7 equal and still 

 shorter, joint 8 with a notched margin and almost as long as joint 3. Legs rather 



*Thisparasite is now known as DUophogaster caUfornica Howard, Mr. Howard hav- 

 ing changed the name Tomocera on account of its similarity to Totiiocerus in Thysanura. 



