cS8 [April, 



Jlbstnirts of Icrnit litrrature. 



BY HUGH SCOTT, M.A., F.L.S., F.E.S. 



Barnes, J. H. and Grove A. J. " The Insects Attacking Stored Wheat 

 IN THE Punjab, and the Methods of Combating them, including a Chap- 

 ter ON the Chemistry of Respiration." Memoirs of the Department of 

 Agriculture in India, Chemical Series, Vol. IV, No. (5, pp. l(35-280c?, Nov., 1916. 



This work, the result of the combined researches of a chemist and an entom- 

 ologist, contains much that is highly suggestive, and of great interest, both 

 scientific and practical. The insects found in the stored wheat consist of 

 eight species of Coleoptera and one of Iiepidoptera. Only three, however, 

 are actively responsible for damage to the wheat, namely, the Dermestid 

 Attagenus undulatus Motsch., the Bostrychid Rhizopertha dominica Fabr., and 

 the weevil Calandra oryzae Linn. : the first is known to attack the grain in its 

 larval stage ; the two latter in both larval and adult stages. Of the other 

 species, Laemophloeus sp. (Cucujidae) is only found living on floury frass and 

 gi-ains already damaged by other insects. Tribolium castaneum (Tenebrionidae) 

 was proved by experiment unable to live on sound grains, and is strictly 

 a flour- beetle rather than a wheat-beetle ; practically the same may be said of 

 Latheticiis oryzae (Tenehrionidae). Alphitobius piceus iiy}^^^!^ to be merely a 

 scavenger, and not to attack the grain ; attempts to rear it on wheat in any 

 fonn failed, though it is found in stores that have been damaged or have 

 become damp, and is often associated with attacks by Teruiites. The eighth 

 kind of beetle is Calondra granaria Linn., which was but rai'ely found. The 

 larvae of the Lepidopteron, Hitotroga cerealella Oliv., damage the grain, but 

 were only observed in one district. 



The life-histories of these insects are dealt with in detail, and are illustrated 

 in coloured plates. The bionomics of Attagenus xt,ndulat\t.s exhibits some curious 

 features. The number of its nicnilts varies according to season and sex. The 

 progeny of the same parents may vary in this )-espect, even though kept under 

 identical conditions. Thus, of two larvae derived from a single ? , one passed 

 through seven, the other through four, moults. The former became a $ , the 

 latter a ^ , and as a general rule $ -producing larvae undergo at least one more 

 moult than those which produce males. During the hot dry months the num- 

 ber of movilts is reduced and development is accelerated, Avhile in the rains the 

 number increases. But no constant number can be given even within these 

 seasonal limits. Hibernation in the larval stage occurs, and when 'adverse con- 

 ditions are encountered the insect merely becomes dormant until they change. 

 The eggs are laid among the wheat and usually singly. The larvae do not as a 

 rule bore right into the grains, but gnaw them from outside. Before the third 

 moult they seem unable to attack whole seeds, and can only gnaw those which 

 are already damaged ; but in the later stages they can begin on sound grains. 



In Rhizopertha dominica the adults will eat away the whole starchy interior 

 of the seed, and produce much floury frass on which the young larvae probably 

 feed — at any rate in part. The eggs are laid either loose among, or stuck to. 



