BEETLES. 389 



fields during thf iiight. The insects of tliis family respire under water from a supply 

 of air wbieh tbey earry abmit attached to the puliescence of the under surface of their 

 bodies ; and tliis air, which appears like a sheet of silver beneath the beetle when in the 

 water, is often renewed by the insect comint;- to the surface. 



The life history and habits of some of the Hydro)ihilidiB are interesting in the 

 extreme because of the nest which the females construct and in which they deposit 

 their eggs. This cocoon-like nest is produced by the hardening of .a gelatinous secre- 

 tion from accessoiy glands of the sexual organs of the females, and in it are de|)osited 

 from twenty to over tnw liundr<'(l eggs, according to the species. 'I'lie cocoon is fast- 

 ened by some of these beetles to submerged vegetation, by others it is left to float on 

 the surface of the water, and tlie females of still other si)ecies carry their cocoon about 

 beneath them, fastened between the posterior coxa; aiul steadied by the hind legs, until 

 the young larva' have hatched. The larv;e are recognized, according to Professor 

 J. C. Schi()dte, by their " claw-formed tarsi, which are sometimes wanting, the ter- 

 minal pair of stigmata, the free jirojecting niouth-jiarts, the very short joint membrane 

 of the maxilhe, the connate clypeus and absence of the labrum, the sharji, sickle-formed, 

 imperforate mandibles, the absent or sharp ligula, the want of a neck on the extended 

 head, and the \ cry short, uii.-Lruu'd anal segment." The larva' when first hatched often 

 prey upon one another in the same cocoon; later they feed upon insects which fall 

 into the water, and u])on sii.iils. In the case of the larva* of Jli/drophilns picens, which 

 eat common house-flies with avidity, the nu)de of feeding is curious. Seizing the fly 

 in its jaws, the swiftly swimming larva seeks some place where it can eat it in quiet 

 and security. Having foun<l a suitable place, it rests upon a piece of grass or leaf and 

 projects the head aliove the surface of the watei-, holding it perjiendicularly. In this 

 position it chews the fly into a pulp, using the antenna' as mouth-parts <lin-ing the pro- 

 cess, and sucking the juices of the fly down its throat, which, during the mastication, 

 acts as a tunnel to catch the juices crushed from the fly. The he.ad is ap])arently held 

 above the stirface of the w.ater in order that the juices of the prey shall not be diluted 

 by the water. Aftei- the juices have been sucked from the fly its chitinous parts are 

 rejected, at least by young ffi/ifrnphi/'is larvie, in tiie same way as like innutritious 

 parts of its prey are rejected Iiy scorpions after they have drawn the 

 juices from it. Pujiation takes ]ilace in the ground. 



Among the small species of Hydrophilida; are a number of very 

 convex form, terrestrial habits, and having the middle and hind tarsi 

 with the first joint elongated. Of these small forms s|)eeiesof >Sj)ha ri- 

 diuni have a narrow mesosterniim ami elongated scutellum. S. .tcarti- 

 bceoides is black, with yellow le^s, :i yellow s]iot on the tip of each 



elytron, and just in front of this yellow spot a larger blood-red one. ¥10.' i&i. — Sphm-i. 

 ^^^^ ' 1 • T^ 1-1 • 1 • ilium scarabwoides. 



It lives ni cow-dung m Kurojie, and a single specnnen, perhaps acci- 

 dental in occairrence, has bi'eu reported from Canada. The larv:e of Sjj/ueridium 

 and of Cerci/on, related gcuei'a. live in moist earth and in dunu', and pirey upon 

 dipterous larvie. 



Ilydrohius and Phylliydrux include closely related atpiatic s])ecies which have the 

 middle and hind tarsi not com]iresscd and with the first joint short, and in which the 

 prothorax at the base is as wide as are the elytra. The last of the five exposed ventral 

 segments is entire, and the antennae are nine-joiiited. In Ili/Jrohius the last joint of 

 the maxillary paljii is longer than the third joint. In /'/ii/lhi/dnis the last joint is 

 shorter than the third. JI. ylobosus and P. rotundatus are similar appearing, smooth, 



