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Fig. 40.—Anterior part of Encyrtus larva, 1.2 mm. in length; dorsal face; the cellular masses beginning to form the buds of the wings, eyes, and antennæ: o, eye bud; e, stomach.

Fig. 41.—Older Encyrtus larva, lateral view, showing the buds of the antennæ (f), legs, and wings; oe, œsophagus; q¹, q², q³, buds of the genital armature; x, rudiment of the sexual gland (ovary or testis); u, urinary tube; i, intestine (rectum); a, anus.

Fig. 42.—A still older larva, ready to transform. The imaginal buds of the antennæ, eyes, wings, and legs have become elongated; lettering as in Fig. 41.—This and Figs. 39–41 after Bugnion.

This mode of formation of the head may be observed still more easily in Rhodites, Hemiteles, and Microgaster, from the fact that their oculo-cephalic buds are much more precocious, and that the eyes are charged with pigment at a period when the insect still preserves its larval form.

“... I believe that this mode of formation of the head occurs in all Hymenoptera with apodous larvæ, in this sense; that a more or less considerable part of the first thoracic segment is always soldered to the head of the larva to constitute the head of the perfect insect. The arrangement of the nervous system is naturally in accord with this peculiarity of development, and the cephalic ganglia of the larva to which the ocular blastems later adapt themselves, are found not in the head, but in the succeeding segment (Figs. 39, 40, 41).