31 



small, four-winged Chalcid fly known as Bilopliog aster califomica 

 Howard. A description and figures of both the male and female of 

 this useful parasite will be found in the Annual Report of this Depart- 

 ment for the year 1880, p. 368, and PI. xxiv, Figs. 3 and 4. The name 

 Tomocera, under which this insect was described in the above-men- 

 tioned report, was found to have been previously used for another group 

 of insects belonging to the order Thysanura, and the name Dilophogas- 

 ter was therefore substituted for it. I have quite frequently found 

 orange trees upon which fully 80 per cent of the adult Black Scales 

 had been destroyed by these parasites. I find by reference to my note 

 book that I bred parasites of this kind on the 14th and again on the 

 27th of June from Black Scales collected on the 25th of the preceding 

 April ; and that on the 22d of September I found a full-grown larva 

 of this parasite under an adult Black Scale. I also captured specimens 

 of this Chalcid on the following dates : January 17, July 2, August 31, 

 September 21, and October 12. This would seem to indicate that at 

 least two and perhaps even three generations of these parasites are 

 produced in one year. 



It is to be regretted that these useful parasites sometimes fall a prey 

 to other insects, but such is the case. I find by reference to my note 

 book that on the 21st of September I saw a larva of a slender greenish 

 bug known as Diplodus renardii Hoi. engaged in feeding upon one of 

 these parasites ; the beak of the larva was inserted into the body of the 

 Chalcid fly and the juices of the latter had been nearly extracted by 

 the voracious captor. Fortunately, these predaceous insects are not 

 abundant. I have occasionally seen them preying upon other kinds of 

 Chalcid flies besides the Dilophogasters ; on the 1st of September I 

 captured one of the adults which had its beak inserted into a Perilam- 

 pus sp., one of the Chalcid parasites of the Lace- wing referred to above 

 in the chapter treating of the Bed Scale 5 the Diplodus held the Chalcid 

 beneath his front feet, somewhat as a dog holds a bone while gnawing 

 it. I have occasionally found the square or roundish egg masses of this 

 Diplodus attached to the upper surface of the leaves of orange trees ; 

 each mass contains from thirty to forty eggs which are regularly ar- 

 ranged in rows, the eggs in one row alternating with those on either 

 side of it. Each individual egg is nearly cylindrical in form, of a honey- 

 brown color, except the top, which is white, and near its center is a 

 small puncture as if made with the point of a needle. The mass is 

 fastened to the leaf by a very sticky substance, which, however, does 

 not hold it firmly, and the egg mass may be easily removed from the 

 leaf with the thumb and fingers of one hand. The adult Diplodus 

 measures nearly half an inch in length, is rather slender, and of a 

 yellowish-green color variously marked with black and yellow. 



Notwithstanding the immense numbers of Black Scales and their 

 eggs which are annually destroyed by the Dilophogasters, still these 

 scales frequently become so abundant as to render it necessary to em- 



