82 [September, 



On i-eference to Signoret's figure, we find three spines or hairs 

 close to the margin of the abdominal segment, just above the base of 

 each median lobe, which are not mentioned or figured by Comstock, 

 nor have I found them in any of the individuals which I have 

 examined of the European A. rapax. 



Signoret also gives five similar spines arranged transversely on 

 the dextral side of the anus, and three similarly arranged on the 

 sinistral side. These are not to be found in A. rapax. 



Again, in Signoret's figure the median lobes, although showing 

 similar and similarly situated notches to those of A. rapax, are not 

 quite of the same shape. Those of A. camellice appear to be of a 

 considerably longer form than those of A. rapax. 



It would not, perhaps, be prudent to attach much importance to 

 any difference which may appear to exist between the anal plates, as 

 drawn in Signoret's figure, and those of A. rapax, as I do not think 

 that Dr. Signoret makes these play so important a part in character- 

 ising species, as Prof. Comstock has more recently shown to be 

 necessary. 



There is yet one more, and as I think an important, point of 

 difference between the two species. A. rapax has an entire ventral 

 scale, that is to say, if the insect is turned over, it will be found com- 

 pletely enveloped in its scale, both ventrally and dorsally, which does 

 not occur in some species ; for instance, A. nerii, which has a mere 

 white film ventrally, and this remains on the leaf when the insect is 

 removed. It can scarcely be supposed that such a character would 

 have been overlooked by so distinguished an entomologist as Dr. 

 Signoret ; on the contrary, we find that he observed this character in 

 one species under his examination, and he considered it of suflicient 

 importance to establish a new genus, which he named Targionia, in 

 order to include this one species with an entire ventral scale (See Ess. 

 sur les Coch., 1870, pp. 105, 106, vel. Cocc, p. 149). This genus has 

 since been abolished by Prof. Comstock, for reasons which he gives in 

 his Sec. Eep., 1883, p. 82. The absence, therefore, of any record 

 by Signoret of a ventral scale in his A. camellice must, I think, be 

 considered important. 



Of course, as is well known, the difference in many of the species, 

 and especially in those which are closely allied, of the genus Aspi- 

 diotus is slight, and only to be observed by microscopical examination. 

 But as the anal plates of the insect may, perhaps, not unreasonably 

 be supposed to assist the insect in weaving its scale, it may not be 

 improbable that the difference in the appearance of the scales, which 

 is observed in different species, otherwise very similar, may be caused 

 by the differentiated form and number of the marginal plates. 



Villa Nova da Gay a, Portugal : 

 July 28th, 1887. 



