OF WASHINGTON. 351 



A NOTE ON THE PARASITES OF THE COCCID^E. 

 BY L. O. HOWARD. 



Dr. Bergroth in a recent letter has called my attention to cer 

 tain statements made by C. Aurivillius in a paper entitled " Ar- 

 rhenophagus, ett nytt slagte. bland Encyrtiderna," published in 

 Entomologisk Tidskrift, Volume IX, Nos. 3-4, 1888, concern 

 ing the economy of some parasites of bark lice. Owing to my 

 unfamiliarity with the Swedish language, I was acquainted only 

 with the Latin descriptive portion of this paper up to the time of 

 receiving Dr. Bergroth's letter. Mr. Linell has since done me 

 the favor to translate Aurivillius' general remarks, from which I 

 may quote as follows : 



Since a few years occupied with the study of our Coccids, I have also 

 paid attention to the peculiar forms of the family Pteromalidae that are 

 parasites of the Coccids. These parasites, that belong to the groups En- 

 cyrtinae and Aphelininae, are generally obtained out of the Coccus female, 

 at the same time or somewhat before the eggs beneath them are hatched, 

 and they appear not in any way to check the development of the Coccus 

 female or diminish the number of the eggs laid by her. These parasites 

 do not, therefore, ruin for themselves their food supply through killing 

 and exterminating their hostesses and their progeny, like most other 

 parasites do, but are satisfied with the excess of food that is on hand. 

 Different is the case with the species that parasitize in the male larva of 

 the Coccids. These destroy entirely the male larvae. That this is the 

 truth is most easily proven with those species whose male larvae almost 

 from the very start are different from the female larvae. This is the case 

 especially in the species of the genus Chionaspis, whose male larvae are 

 covered with a narrow shield with parallel sides, while the shield of the 

 female larvae is broader. In regard to other genera, for instance in the 

 family Lecaniidae, that have in the first stage similar larvae (in both sexes), 

 it could be advocated that the larvae attacked and killed by the parasites 

 even might be female larvae, although checked by the parasites in their 

 development, so that they never had a chance to become larger than the 

 male larvae. A case that might be thus interpreted I have observed in 

 Pliysokermes hemicryphus Dalm. On a small low spruce shrub I dis 

 covered 'in Roslagen) last summer females of this species in great num 

 bers attached in the usual way in the lower leaf angles of the second-year 

 shoots. But on the leaves of the same shoots were found here and there 

 some quite small parallel-sided coccids which I considered male larvae and 

 carefully preserved in the hope of obtaining out of them the hitherto 

 unknown male. I was disappointed in this, and got from nearly one hun 

 dred small coccids that I collected from the leaves only a small parasitic 

 Hymenopter (Aphycus sp.), one out of each. In this case either every one 

 of the collected male larvae has been attacked by a parasite, or we must 



