OF WASHINGTON. 171 



having great power of elongation, so that in life and when 

 feeding it reminds one of some great Syrphid larva. When at 

 rest, with the head bent over on the breast, it measures at full 

 growth about one and one-eighth inches to two inches. The 

 skin is nearly smooth, but with a slight rugosity and flecked 

 more or less with whitish spots, especially between the seg 

 ments. There are ten pairs of reddish-brown spiracles, one for 

 each segment from the first to the tenth. The head is resinous 

 in color, and the mouth-parts are remarkably well-developed as 

 compared with other aculeate hymenopterous larvae. The 

 clypeus, labrum, mandibles, maxillae and labiu'm are quite as 

 prominent and perfect as in many Coleopterous larvae. The 

 mandibles are very strong, somewhat obtusely pointed, and 

 have, a short distance below the 'apex, a prominent tooth. 

 They are dark brown, almost black at tip, paler at the base. 

 The maxillae are large, fleshy organs, terminating in two 

 brownish horny processes, one of which doubtless represents 

 the maxillary palpus. The labium is also a fleshy organ and 

 bears two horny processes representing the lingula. It has 

 also a spinneret. The antennae are very rudimentary and are 

 represented by two minute whitish elevations on the front. 



The cocoon is constructed very rapidly, not more than two 

 days being required for this purpose. Irregular threads are 

 first thrown out and attached to whatever they may touch 

 both the Cicada and the surrounding wall of the cell. The 

 cocoon, which at first consists of an open cylinder, is con 

 structed of silk, with enough earth incorporated to make a 

 rather dense pod, and is of an irregular elongate-ovoid form, 

 tapering somewhat toward the posterior end, and varying 

 in length from one and one-half to three-quarters inches. 

 The interior is loosely lined with a coarse yellow silk, except 

 for an area in the middle, covering from one-half to two- 

 thirds of its inner circumference, where it is densely covered 

 with a fine white silk. In this light area, and covered by the 

 silk, are to be seen from eight to twenty dark-brown slightly 

 elevated spots. These spots are caused by a resin-like sub 

 stance employed to cap certain very anomalous hollow tubercles 

 which project from and open on the exterior of the cocoon. 

 These tubercles are constructed of the same resin-like brownish 

 substance, and in their perfect form and size greatly resemble 

 spiracles. They are capped, as described, evidently after the 

 completion of the cocoon. These curious little tubes I have not 

 noticed in the cocoons of any other sand or fossorial wasp, and 

 their purpose is somewhat problematical. My first impression 

 was that they were little pellets of excrement, being the last 

 faeces excreted by the larva about the time of completing its 

 cocoon, and that, having viscid and solvent qualities, they had 



