1913.] ' 243 



Ortholitha peribolata, Hiibn.— Cork Woods, October, 1887. J. J. W. 

 Larcntia bilineata, L. — Cork Woods, Jtily. J. J. W. 

 Stemmatophora gadesialis, Eagonot.— San Roque, Jxily, 1887. J. J. W. 

 Aso2na glaucinalis, L. - Gibraltar, October, 1S87. J. J. W. 



" La Casa," 



99, Bensham Manor, Thornton Heath : 

 June, 1913. 



THE LIFE-HISTOEY OF A NEW FAMILY (MICROMALTHID.^) 

 OF BEETLES. 



BY HERBERT S. BARBER. 



Mr. H. S. Barber's accouut of the life-history of the single known 

 species of this family of Malacodenn Colerrptera [Proc. Biol. Soc. 

 Wash., XXVI, pp. 185-190 (Aug., 1913)] is so interesting that we 

 take the oppoi'tiinity of reproducing a portion of his paper. The 

 family 3Iicromalthkhv is nearly related to Lymexylonidee, and is at 

 present nionotypic, being based upon Micromaltlnts debilis, Lee, from 

 North America, an insect having the general facies of Hydnocera of 

 the family Gleridai.—'EBS. 



" During an attempt, still progressing, to secure by breeding all of the stages 

 in the paedogenetic beetle, Micronialthus debilis, Lee, certain astonishing facts 

 have become evident which make the life-history of this beetle the most 

 remarkable in the Coleoptera, if not one of the most remarkable in the whole 

 class Insecta. Although still far from complete the publication of the life- 

 history, as now known or foreseen, may cause students investigating other life- 

 histories to look for hitherto unsuspected features in their problems, which if 

 not really looked for, would pass unnoticed. 



Micronialthus presents perhaps the most plastic larval forms yet known, 

 combined with a practically fixed adult form of wide distribution. No close 

 relatives are known, and it seems remarkable that specimens from Michigan, 

 Kentucky, and Virginia should exhibit no tendency towards local variation in 

 a species apparently of such feeble powers of migration. It combines in its 

 life-cycle —eggs by two methods of reproduction, seven or eight forms of larva?, 

 adults through two distinct lines of larvse, ovii^arous psedogenesis and vivi- 

 parous pedogenesis. The species appears to present a beautiful case of 

 sex-determination, and this also seems to be an effective barrier against 

 inbreeding ; for males and females of the same brood appear unable to issue 

 simultaneously on account of the interpolated larval stages of the former 



The breeding of the specimens is not difficult, except when too frequently 

 disturbed. The larvae do not appear well able to x-e-adjust their surroundings 



V 2 



