194 ' l February, 



It appears to me that the marginal spines will often assist in deter- 

 mining the somital divisions, and I will now endeavour to trace out 

 the complete number of abdominal segments in the three sub-families 

 of the Diaspina, Lecanina, and Coccina. 



As types of these sub-families I take by way of illustration, as before, Aspidiotus 

 nerii and Mytilaspis pomorum, Leeanium olece, Dactylopius citri, as shown in figs. 1, 

 2, 4 and 5. Figs. 1 and 2 represent the abdominal segments only, drawn from the 

 dorsal side, but partly diagrammatic, in order to show the Tentral grouped glands 

 before referred to. In fig. 2 {Mytilaspis pomoruni), which is more highly magnified 

 than fig. 1, I have traced where I suppose the segmental divisions would occur ; but 

 in fig. 1, I have drawn this part of the abdomen as it actually appears in a properly 

 prepared specimen. 



In fig. 5 (representing Leeanium olece) the first six abdominal divisions are 

 daawn as they are found in Nature, the eleventh or last segment being represented 

 by the anal cleft, and that which is termed by Targioni-Tozzetti the " precaudal 

 segment," appears to me to contain really four rudimentary segments, as indicated 

 by the marginal spines. It will, therefore, be seen that in the Lecanina, as in the 

 Diaspina sub-family, the last five abdominal segments have undergone considerable 

 modification. These segments, including the eleventh or " anal cleft," are shown 

 more highly magnified in fig. 6. 



In fig. 4 (representing Dactylopius citri) the first eight abdominal segments are 

 drawn as they are found in Nature, and the ninth appears to me to contain really 

 three segments telescoped into one another, as shown in figs. 7 and 8, each segment 

 having a spine on its margin, and so constituting what has been termed the ano- 

 genital ring with six hairs, and which, when the insect is mounted with " pressure," 

 presents the appearance more or less of fig. 7. These six anal spines during the life 

 of the insect appear as two waxy processes joined together protruding from the 

 anus. The secretion with which they are agglutinated differs from the powdery 

 secretion of the other segments, and it may be observed proceeding in the form of a 

 bubble from the end of these six agglutinated hairs, like the honey-dew of the 

 Aphis. I had not observed this until I read Mr. Maskell's interesting work before 

 referred to. 



Having now glanced at the terminal segments of the genus 

 Dactylopius, it will be more easy, I think, to comprehend the nature 

 of my suggestion that a similar manner has been adopted by Nature 

 of modifying the corresponding segments of the genera Aspidiotus 

 and Mytilaspis, as shown in figs. 1 and 2, as well as in the other genera 

 of the Diaspina. On referring to. figs. 1 and 2, it will be seen" that 

 the marginal lobes appear to be in fact the lateral terminations of each 

 segment, whilst the emarginations or incisions seem to be the openings 

 of the marginal simple secreting glands, which are usually each ac- 

 companied by an adjacent plate (squame). Each segment shows, a 

 spine, as will be observed in both figures, so that what Prof. Comstock 

 has termed lobes, spines, and incisions, become important characters, 



