52 Annals Entomological Society of America  [Vol. VII : 
squarely through these grouped spinnerets, often show a heavily 
nucleated invagination of the hypoderm, but aside from this 
no inkling as to the function can be ascertained. Just before 
the insect commences egg-laying, however, a white powdery 
substance can be found issuing from the openings, and sections 
made from the material killed at this time brought out the 
gland cells in their minutest detail. A slender duct (Plate 
XIV, Fig. 17-c) is found to connect each of the circular openings 
with the wax secreting glands. These units vary in number 
of cells from one or two to six or seven, each division possessing 
a prominent nucleus and uniting with the main duct by a slender, 
thread-like lumen. Between these ducts are numerous elongate 
supporting cells (Plate XIV, Fig. 17-b) which have no relation 
with the functions of secretion, except that they may aid in 
keeping the passageway open. 
The spinnerets are circular, rather lens-shaped, and made 
of chitin, through which a minute pore is found connecting the 
cell and duct to the exterior. This opening seems always to 
be uniform in its makeup—a rosette with five small parts. 
Prof. E. E. Green is the author of a general rule which 
can be applied to Coccids possessing these glands, that they 
are for the most part ovo-viviparous, or egg-laying, while 
those that do not possess these spinnerets are viviparous. 
I have made observations on a number of the local species 
and find the rule to hold true. I have also noted that the 
embryo reaches a greater state of development before the egg 
is deposited in the cases of those species in which there are 
very few spinnerets, than in those that possess a large number 
of grouped glands. In Aspidiotus uvae the circumgenital 
glands are found in very small numbers, two or three in a group, 
and the species is reported to be viviparous. The opportunity 
of studying a large series of these insects might reveal some 
very interesting facts. One can easily make a mistake in 
examining material for this phenomenon by using adult females 
which have died containing well developed eggs. The eggs 
are not destroyed by the death of the mother, but from them 
hatch young, around which is the shriveled skin of the mother, 
and through which there is no means of escape for the newly 
hatched insects. Such material when mounted impresses one 
as being of a viviparous form. Circumstances of this nature 
may be the explanation of some of the seeming exceptions to 
the rule. 
