PSEUDOCOCCUS ACERIS. 181 



fatal traps entangling any male coccids that may walk 

 into tliem. 



The foregoing observations were made from a large 

 colony of the insects infesting a laburnum, which 

 for a number of years past has been under almost 

 daily observation. The colonies on gorse differ some- 

 what in habit from those found on laburnum, which 

 I presume is due to the much more limited areas 

 over which the insects are able to disperse themselves. 

 Thus the male puparia on gorse are chiefly found 

 among the spiny leaves, and the ovisacs generally on 

 the main stems of the food-plants ; but they may be 

 found together both upon the leaves and the branches. 

 I have not been successful in obtaining males on any 

 other plants but the laburnum and gorse ; it is, there- 

 fore, highly probable that the females are occasionally 

 parthenogenetic . 



I have carefully examined examples of Mr. Douglas's 

 types, and have also re-examined my own, and have 

 come to the conclusion that we have been relying too 

 much on the antennal formula of the adult females, 

 which, like that of the antennas of many other coccids, 

 is given to variation, and cannot be, as hitherto, im- 

 plicitly relied upon in the differentiation of species. 

 The forms described by Mr. Douglas and myself as 

 distinct species are undoubtedly all specifically the 

 same, and I think I have correctly referred them to 

 Signoret's P. aceris. As to the American P. aceris, it 

 is evidently quite distinct from the European species, 

 and will, as already stated, require a new name. 



EXPLANATION OP THE PLATES. 



PI. C, fig. 1, Vol. I. Insects (ovisacs) natural size in 



situ on gorse. From a photograph. 

 PI. LXIII, fig. 1. Adult female at period of gestation 



(dorsal). X 10. 



Figs. 2, 2 a. Antennae of adult female. X 140. 

 Fig. 3. Leg of the adult female. X 140. 



