EMBRYOLOGY OF CHRYSOPA. 567 
and Hemerobidz) are endoblasts, to use Dr. Dohrn’s terms. -On 
inquiring how far these two modes correspond to the degree of 
development of the insect on leaving the egg, and the degree 
of metamorphosis of the insect before becoming adult, it seems 
that the endoblasts occur in those ametabolous insects (Hemiptera 
and Neuroptera) with flattened, leptiform larvae, and also in those 
——— with similar larve, as distinguished from the weevils, 
ich have eruciform larvee, i. e., resembling the maggots of Dip- 
ks and Hymenoptera. The two modes of development, then, do 
not fully accord with the two different degrees of metamorphosis 
of insects, but more probably depends simply on the form of the 
larva when hatched. Now there are two forms of insectean larvæ 
which are pretty constant. One we may call leptiform, from its 
general resemblance to the larvæ of the mites (Leptus). e lar- 
væ of all the Neuroptera, except those of the Phryganeidæ and 
Panorpidæ (which -are cylindrical and resemble caterpillars), are 
more or less leptiform, i. e., have a flattened or oval y, wi 
large thoracic legs. Such are the larvæ of the Orthoptera and 
Hemiptera, and the Coleoptera (except the Curculionidæ ; possibly 
the Cerambycidæ and Buprestidæ, which approach the maggot-like 
form of the larvæ of weevils). On the other hand, taking the cater- 
pillar or bee larva with their cylindrical fleshy bodies, in most 
respects typical of the larval forms of the Hymenoptera, Lepidop- 
tera and Diptera, as the type of the eruciform larva, we find that 
those insects with such larve are ectoblasts. (The Podure which, 
as in Isotoma, are ectoblasts, and are certainly leptiform when 
hatched, form an apparent exception.) Thus the two modes of 
development (ectoblastic or endoblastic) perhaps simply depend 
on the form of the insect when hatched, and its mode of life. 
The leptiform larvæ of insects may be compared with the nau- 
plius form of Crustacea, and in a much less degree the eruciform 
to the zoea form. The three higher suborders of insects may be 
compared to the Malacostraca with their zoez form larva, and the 
four lower suborders (Coleoptera, Hemiptera, Orthoptera and Neu- 
roptera) with the Entomostraca,* in which certain forms, as in 
some Phyllopods, and Limulus, and the Trilobites, are hatched in a 
subzoea condition (corresponding to the eruciform larve among 
the-Neuroptera and Coleoptera). The larve of the earliest insects 
Entomostraca J fi i not that they 
J 
* The terms Malacostraca 
are entirely natural divisions. 
