39 



several weeks, the insects still continued to increase and spread 

 to other granaries." An outbreak of this pest very rarely occurs 

 -vhere chickens could be utilized for its destruction, and they are 

 therefore of little practical value in this connection. 



Mammals. — I have here to relate a curious instance where a ccm- 

 mon house mouse, 3fus miisculiis, devoured several hundred puj se of 

 the flour moth in one evening. April 11, 1895, I removed a male 

 and a female flour moth, still pairing, from a stock cage, and placed 

 them in a separate cage in order to obtain the eggs for experi- 

 mental purposes. The eggs were laid and hatched in due season, 

 the first young appearing April 21, and the larvas were supplied 

 with an abundance of wheat flour and caimeal for food. The larvae 

 matured and were all pupated by June 5, the brown chrysalids 

 being plainly seen through the sides of the glass cage. By actual 

 count there were two hundred and fifty-four pupse in the cage at 

 this time. A mouse discovered this cage sometime during the 

 night of June 12, cut through the Swiss muslin that covered it, 

 and devoured every pupa within. Little or rone of the flour and 

 meal in the cage had been eaten. Of course, millers and dealers 

 can turn mice to no good account as enemies of the flour moth, 

 and this instance is introduced t imply as a record of the evident 

 relish of one mouse for insect pupae. 



Predaceouslnsects. 

 -Those insec's pop- 

 t ularly known as 

 "flour weevils" are 

 foremost in this 

 group. They are 

 jjr known to science as 

 t^^-~ Tribolnim ferritgme- 

 iLm* and T. con- 

 fusum. The two spe- 

 cies are so closely 

 T related that they can 

 I with difficulty be sep- 

 arated, and, to the 

 ordinary observer, 



Fig. 5.— Tribolium confnsum; a, adult beetle; b, larva; c, pupa.— they are One and the 

 all enlarged; d, lateral lobe of abdomen of pupa; f, head of beetle. c.f,.™Q fln'ncr TliAir 



showing antenna;/, same of r. /e/Tug'i'/ieMm,— all greatly enlarged. °"'^« tuiug. ^ -^""^-^ 



(After Chittenden.) habits are sjmiliar, 



and the injniies occasioned by them far outnumber those of any 

 other insect that attacks grains and farinaceous foods. Both spe- 

 cies are cosmopolitan, and have a wide geographical distribution. 



• In speaking of the flour moth larvre Professor Zeller says: "Simultaneously with these 

 larvtB [ received the little beetle Tribolium ferrugineum, which multiplied so rapidly that during 

 the summer I sometimes found large masses of its yellowish larvre. I eagerly destroyed them, fear- 

 ing they would, at least, be disadvantageous to the larvie and pnp;u of the flour moth. Now, it 

 seems to me that this beetle was unjustly held in suspicion by me, and ibat it and its larvK, at 

 most, would help to devour the moths reared for propagation, and dying soon after mating." From 

 this it appears that Prof. Zeller did not observe the weevil feeding upon the larv« or pupsc of the 

 flour moth. In the same paragraph, however, he says: "I rather suspicion the Kphestia iarv;e of 

 devouring little by little, not only their dead parents, but also the pupae which have fallen out of 

 the web." I have myself seen the flour-moth larvte attack and devour pupa; of their own kind in a 

 breeding-cage where the pupiu had been uncovered. 



