May 1S91.] 



PSYCHE. 



79 



In an introductory paragraph he 

 says: "Prof. H. Garman justly calls 

 in question (Psyche, v. 6, p. 29; Feb. 

 1S91) a statement made in Insect Life 

 (v. 1, p. 59) where, by a typographical 

 oversight, the Twelve-spotted Diabro- 

 tica is stated to have 'bred upon' in- 

 stead of 'fed upon' melons. The error 

 is self-evident from the language and 

 from the tenor of the article which does 

 not treat of larval habits at all but of 

 the food-habits of the beetle." 



"My knowledge of the corn-feeding habit 

 of the larvae of this insect dates from April 

 30, 1SS3, when Judge Lawrence Johnson for- 

 warded to me from Allenton. Wilcox Co., 

 Ala., a number of larvae of which he wrote 

 as follows : 'I sent you last week from Allen- 

 ton specimens of the same destructive 'bud- 

 worm' that I once mentioned as heard of but 

 not seen. This is about the right time, for 

 they are now going into the pupa stage and 

 in the sand you will find one of the pupae. 

 The worm leaves the corn after doing its 

 mischief and the pupa referred to was found 

 immediately under the stalk among the roots. 

 I have never met with this worm except in 

 the prairie regions of southern Alabama, but 

 have heard of it in Mississippi.' " 



From these larvae Professor Riley ob- 

 tained adults May 21, 1SS3. He ob- 

 tained larvae and beetles from Missis- 

 sippi in 1SS4 where they are said to 

 abound in corn fields from March to the 

 middle of May. In June, rSS6, they 

 were reported to him as injuring corn 

 at Mt. Vernon, Va., the result being a 

 withering and drooping of the central 

 parts, while in some cases the plants 

 were killed as soon as sprouted. 



The eggs were obtained by Professor 



Riley from females confined with earth, 

 and were placed in the soil as in the 

 case of D. longicornis. Larvae col- 

 lected June iS from infested corn at 

 Mt. Vernon, Va., changed to pupae 

 June 22, and beetles emerged July 6, 

 and produced eggs on the following 

 day. Larvae from these eggs were first 

 observed July 15. In this connection 

 Professor Riley continues: 



''The above indicates that this insect is at 

 least double-brooded, in which respect it dif- 

 fers in habit from the closely allied D. longi- 

 cornis which is single-brooded and winters 

 usually in the egg, though occasionally in 

 the adult state. The second brood of Dia- 

 brotica 12-punctata doubtless winters over, 

 and deposits eggs about the young corn or 

 other plants in the spring. Eggs of the last 

 brood are also doubtless deposited in the fall, 

 and winter over, as is usually the case with 

 D. longicornis." 



I am not at present prepared to be- 

 lieve that the female D. iz-ptuictata 

 produces eggs in the fall of the year. 

 Careful examination of examples taken 

 whenever possible has failed to show 

 ova in the ovaries at any time except 

 in the early spring just before the first 

 brood of larvae appear, and again when 

 these larvae become beetles. After 

 these adults have deposited their eggs, 

 no gravid females occur again until the 

 following spring. The search for them 

 has been especially thorough in the fall 

 and winter, and among all the exam- 

 ples dissected during these periods not 

 a single one showed any signs of de- 

 veloped ova. 



"The early stages of D. u-punctata are 

 scarcely different from those of D. longi- 



