M;\V MI|;I< STATK MTSKI \l 



mass is boiled or treated with hardening agents. The interior 

 of the cylinder is I raversed by interwoven cords. As many as 19 

 spires hiivc been counted in one egg mass and since each spire 

 commonly contains about I." e^gs, the total may amount to 850 



or even more." 



In an nndricrminrd Norili American species observed b\ the 

 writer. the egg mass is in ihc form of a cliini]) enveloped in gela- 

 tine. which is moored l>y means of a coi-d lo a stone or a weed 

 along ihe hank of a pool. The eggs within this elumji have no 

 definite arrangement but lie at random Hig.lui. Another North 

 American species lays a siring in which the eggs are arranged 

 -ho\\u in lig.l.~. and still another as shown in lig.12. 



Larva. All the larvae of the numbers of this group are rather 

 slender. ha\e a rather short head, and possess thoracic and anal 

 pro legs ipLlCi. In si/.- the mature larvae \ary from 4 or 5 mm. 

 to upwards of i 1 .". mm. .Many of the largest species are blood red 

 in color, while the smaller ones are yellow, light or dark green. 

 brownish, or pink. The head is small, brownish in color, heavily 

 chit ini/.ed. and a lit t le longer t ban wide. The sch-rites of the head 

 ..insist of a doi>al. \eniral. and two lateral plates, besides a num- 

 ber of smaller ones. The dorsal sclerite is elongate shield-shaped, 

 often with a few setae. Attached to the front margin of this 

 plate is the labrum. which hangs Hap-like in front of the mouth 

 and may be bent backward; and on the under surface are several 

 pairs of setae, usually pectinate. Attached to the ventral surface 

 of the labrum is the epipharynx. This is a rather complex struc- 

 ture; it is attached at its anterior margin, its free margin projects 

 ventrad and caudad. Its form varies in the different genera. 

 The lateral plates bear two pairs of rudimentary eyes (pigment 

 spots) as well as the antennae and the jaws. The antennae (pl.16, 

 fig.5, and pl.22, fig.la) are situated on the anterior end of the 

 lateral plates; they consist of a comparatively long basal joint 

 and several shorter terminal ones. The mandibles (pl.22, fig.l, 

 md) situated ventrad of the antennae are stout and have a four or 

 five, toothed margin. They are articulated in such a manner that 

 they move in an oblique plane, striking the labium (pl.16, fig.5). 

 The labium is attached or rather is coalescent with the front 

 margin of the ventral sclerite of the head, the suture separating 



