1913.] 245 



It is believed that males only are developed from tlie mother-devouring 

 Cnrculioid larva hatching from the single egg of the oviparous pasdogenetic 

 form, and that the amount of animal food taken by the young Caraboid larva? 

 in feeding after birth upon the body of their viviparous pajdogenetic mother 

 may govern the development of females or the oviparous ptedogenetic form 

 instead of viviparous pa3dogenetic individuals. Other factors, however, m^ist 

 of course play important parts, and it is quite possible that a change of the 

 wood to a dryer, warmer condition may force a majority of the develojiing 

 brood of feeding larva; out as females. 



The provision against inbreeding, before alluded to as the series of inter- 

 polated larval stages of the male shoiild be better explained. The Cerambicoid 

 larva, to produce a female, simply changes to pupa and issues very shortly as 

 adult ? ; while one that will produce a male must become in seqtience : — 

 uni-oviparovis psedogenetic form,— egg, — Curculioid 1st larva,— metrophagous 

 larva,— short-legged prep vipa,— pupa, and adult J . By this time all of his 

 sisters will have lived their short lives and died. 



A detailed account of one of the most significant series of observations, in 

 which the progeny of one psedogenetic mother developed to reproduce by all 

 three methods above shown, may put the matter in a clearer light to the reader. 



A colony of larva; was foimd in a pine log at Natural Bridge, Ky., in 

 September, 1912, by Mr. T. E. Snyder, who gave some fragments of wood con- 

 taining Cerambicoid larvae to the writer on January 3rd, 1913. These were 

 placed in a plaster cell, and on February 8th the colony was found to be 

 maturing into psedogenetic individuals. From these latter a number of isola- 

 tions were made, and one large community cell was started of the progeny 

 foimd in the cell of a psedogenetic mother whose shrunken body had probably 

 been consvuned by the young, as has since been almost proven to be the rule. 

 These twenty-one, first-stage, legged larvse were placed in a plaster cell in a tin 

 box and supplied with food in the form of fragments of decaying wood from an 

 oak stump, in which the writer had failed to find evidence of this species. 

 In an hour the larvse had all disappeared, but later one was found dead with 

 the fungus disease (?) that causes these larvse to turn pink, die, and then throw 

 out fine radiating white filaments for nearly a millimeter in all directions. 

 Some others probably died earljr. After two months some of the chips were 

 broken up, and larvse of about 3 mm. in length were found. Luckily, on 

 July 1st, almost five months after starting the breeding cell, the contents were 

 carefully examined. Sixteen of the original twenty-one were fovind in the 

 following conditions : — 



Seven were full-fed larvse, in two of which the psedogenetic form could 

 be seen ready to moult. 



Four were in the psedogenetic stage, but did not display embryos within 

 body, and subsequently died (apparently barren). 



Two were represented only by the cells in which the psedogenetic form had 

 developed, given birth to young and been consumed by them; six 

 young being in one cell and seven young in the other. 



