l()i)8 FAMILY LIM. — OllK VSOMKI.IDJ':. 



c. Front of head normal, not intlexert, mouth anterior. 



/. Last dorsal segment of abdomen not exposed; middle ventral seg- 

 ments not narrowed. 

 //. Antenme widely separated at base, usually more so than the 

 length of first joint. 

 /(. Front coxaj rounded; third tarsal joint bilobed. 



Tribe VII. Eumolpini. j). 1\'.'A. 

 hh. Front cox;e transverse; third tarsal joint usually entire. 



Tribe VIII. Oukysomeltni, p. 114'.). 

 (jil. Antenna' rather close together at base, inserted on the front; 

 front coxie conical and prominent. 

 /. Hind thighs slender, adapted for walking. 



Tribe IX. (iALKuuciNi, ]>. IK'd'. 

 //. Hind thighs thickened, adapted for leaping. 



Tribe X. IlAi.rKiisi. \\. 1177. 

 ff. Last dorsal segment of abdomen exposed and sloping downward ; 

 form of body robust, compact, siibcylindrical. 

 j. Surface of body coarsely tuterculate above; antennte received 

 in marginal grooves on the lower side of thorax. 



Tribe V. Ciilam vdini, p. 1111. 

 //. .Surface of l)ody not tuberculate; antennae not received in 

 grooves. 

 /,-. Prosternum not separating front coxfo; antenme short and 

 serrate. Trilir W . ( 'i.ythkixi. p. \W1. 



A/.'. I'rosternum extending between front coxjie; antemue usually 

 long and slendei'. Ti ibi' \'l. ( "hyptockpiiai tni. p. lilti. 

 vv. Front of head iuHexed, mouth inferior; form oblong, wedge-shaped, 

 broad and truncate behind; surface usually strongly ])itted (►r 

 reliculaled. Tribe XI. lIisiMXi, ]). VS1'.\. 



U(t. Thorax and elytra with broad, expanded margins; head (in our spe- 

 cies) concealed; outline of body elliptical or nearly circular. 



Tribe XII. Cassiimm. p. ]-'2H. 



Tribe I. DONACIINI. 



Ohlony, gracoriil ])ectles of iiicdiuin size which occur upon the 

 leaves and stems of water-lilies, arrowhead, pond-weed, skunk eab- 

 ha^e, pickerel weed, reeds, sedges and other water-loving plants, 

 and hence are semiaquatic in hahit. In form and general appear- 

 ance they resemble certain Ceramhycida^ and constitute a, connect- 

 ing link between that family and the present. The lar\^a' li\'e on 

 the outside of the submerged roots of the plants above mentioned, 

 and obtain their supply of air through the tissues of the plant. 

 "When about to change into pupa?, they enclose themselves in silken 

 cocoons, a number of which are often found fastened in a row to the 

 stems or roots of the acpiatic plants. The mature beetles are more 

 or less gregarious, and fly al)out on bright siumy days, alighting on 

 the leaves or flowers in numbers. 



