358 R. T. LEWIS ON LARVAL FORMS OF ORTONIA AND ICERYA. 



had been put aside in August, a re-examination of which might, 

 perhaps, throw some further light upon the matter. I found them 

 all dead, each with its train of wool behind, but on turning them 

 over I had the satisfaction of discovering upon the under side not 

 only that some of the eggs had recently hatched, but also that a 

 number of living larvae were still clinging to the body of the mother. 

 On placing them under the microscope it was at once apparent 

 that my hope had been well-founded, and that sufficient differences 

 existed between the larvse of the two forms to impress even a 

 casual observer with the fact that he had before him two distinct 

 species. Having made drawings upon the same scale of the larvae 

 of each form, I forwarded them to Mr. Douglas, and was glad to 

 hear from him in reply that he regarded the evidence thus afforded 

 as quite conclusive in establishing the fact that the two kinds were 

 entirely distinct from each other. . . 



In illustration of these notes I have placed under a microscope 

 in the room some living larvae of. leery a, whilst under another is 

 shown a mounted specimen of the larva of Ortonia ; I also submit a 

 drawing of each, made accurately to the same scale, in order to facili- 

 tate comparison. On examining these (see Plate XXVII, Figs. 1 

 and 2) it will be seen that the two kinds are alike in having bodies 

 of a bright coral red, and that, so far as the number and proportion 

 of joints of antennae and legs are concerned, there is also a tolerably 

 close resemblance. There is, however, a considerable difference in 

 the size of the creatures, for although of the same age within a 

 day or two, the larva of Ortonia measures *9 x '45 mm., as against 

 •6 x *3 mm. in the case of that of Icerya, a proportion, it may be 

 noted, about the same as that between the average adult specimens 

 of the respective genera. The same relative proportion exists as 

 to the lengths of the antennae, but whereas the two longest 

 terminal hairs carried by Ortonia do not exceed -175 mm., those 

 of the smaller insect measure not less than *825 mm. ; the hairs on 

 the sides of the body, on the other hand, are longest in Ortonia, 

 reaching # 5 mm., as against "1 mm. in Icerya. A still more striking 

 difference is apparent in the long and delicate hairs extending from 

 the posterior extremity. These in Ortonia are four in number, and 

 •85 mm. long, whilst in the smaller Icerya there are six, with an 

 average length of no less than 12 mm., or about twice the length 

 of the creature itself. Each claw in both species is furnished with 

 a pair of the recurved knobbed hairs (absent in the adult) common 



