81 
or compact masses instead of in the more elongate or serial order, seen 
in ancylus and forbest. The anterior group usually has much fewer pores 
than the lateral groups. Six is an average number for the anterior 
group, and ten or twelve each for the four lateral groups. The median 
lobes are large, distinctly notched exteriorly. The second pair of lobes 
are very minute, narrow, and notched, as in the case of the median pair, 
but having a very characteristic form which is quite uniform in differ- 
ent specimens, and furnishes one of the best means of recognizing the 
species. The chitinous processes between the lobes are very small, 
subequal. The plates are minute and inconspicuous. The dorsal pores 
are quite characteristic; there are usually two between the first pair of 
processes, and a row of five or six extending from the second pair of 
Fig. 4. Aspidiotus ostreeformis: Much enlarged view of last segment of adult female insect, with 
tip of same more enlarged above (original). 
processes, and after a considerable interval continued near the lower 
group of paragenital glands in one or two additional pores. <A lateral 
row of about ten or eleven pores extends from near the base of the first 
pair of spines to the lateral chitinous thickenings. Differing from most 
- of its near allies, it has a group of six or seven pores near the basal an oles 
of this segment. Other characteristic features of the anal plate are 
shown in the accompanying figure. 
The anus is very minute and quite distant from the median lobes. 
The spines and minute ventral hairs do not differ from those of allied 
277—No, 20-——6 
