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regularly shaped. For convenience of 'comparison I have lettered the 
ocelli in a definite order, like the stars in a constellation. This con- 
stellation, as has been stated, shows somewhat of the form of the letter 
S. The ocelli are lettered in order, beginning with the one most cephalo- 
laterad in position. In looking through a collection of drawings of 
the ocellar constellations of species scattered throughout the different 
genera, we find ocellus D to be somewhat variable in position. This 
might be termed the central ocellus if we had only to deal with spe- 
cies having the eyespots broad. In forms with the narrower eyespot, 
where ocelli A and E are strung out farther apart, opportunity seems 
to be offered for D to take position on the lateral edge where I judge 
that it is the most useful, for reasons to be stated later. Ocellus H 
is another which is quite variable in position. It oftener shows posi- 
tional affinity with C than with G, though in some instances it seems 
to have moved caudad nearer the latter. Now it may be merely a 
coincidence, but it certainly is true that when there is atrophy among 
the ocelli, these two are usually the first to decrease in size, and . the 
first to be eventually lost. When D is central in position, as in the 
members of that group of Sminthuri including Sminthurus minutus 
MacG., S. i-maculatus Ryder, S. aureus Lubb. and S. niger Liibb,, this 
is notably true, it being always small though not necessarily the only 
small ocellus of the constellar S. See figure 8. Ocellus H appears to 
have usually the slightest hold on existence of any, though some excep- 
tions will be noted. In Sminthurus aureus Lubb., fig. 8, all the ocelli 
excepting D and H are of approximately equal size. Ocellus D, ’which 
is central in position, is very small; while H is yet smaller and is 
somewhat triangular in shape, and is situated close to G. In the 
genus Papirius, Fig. 10, is found a condition which shows the fate of 
the ocellus which becomes crowded toward the center, losing its posi- 
tion upon the margin. Papirius maculosus Schott, Fig. 9, shows H of 
normal size and on the edge of the very convex eyespot. The shorten- 
ing of the eyespot has apparently crumpled the line, forcing C out of 
the marginal row. It is small, though not so small as D, which is also 
nearly central. Some of the species of SmintJiurus show a condition 
similar to the Papirius, though not usually so well marked. Proba- 
bly the shortening of the eyespot is to be co-ordained with the short- 
ening of the dorsal surface of the head, due to the vertical instead of 
horizontal position of the head among the Sminthuridae. The prom- 
inent position of the eyespots is heightened by their own great con- 
vexity, v/hile the positions of the most useful ocelli being around the 
edge of the raised area, an outlook is secured in all directions by each 
eyespot. The insect’s demand for a view straight dorsad seems to oe 
so little as to allow central ocelli to atrophy through disuse. 
In the genus Lepidocyrtus, we find in a typical species, L. purpureus 
Lubb. Fig. 10, a somewhat elongate eyespot. Ocelli D and H are decadent, 
but still present. In this genus there was once an eyeless species, but 
it had the honor of being later considered as the type of a new genus 
Cyphodeiru^s. Two species of Lepidocyrtus which I have described from 
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