THE MEXICAN GRAIN BEETLE. 11 
OBSERVED HABITS. 
In order to obtain information in regard to the habits of the insect, 
a number of living adults was placed in a small rearing jar contain- 
ing fresh meal and slices of raw potato, the latter to furnish addi- 
tional moisture, and placed in a cool room. Here the adults showed 
conclusively that they were perfectly able to withstand the average 
temperature of an ordinary mill, warehouse, or granary of a latitude 
such as that of the District of Columbia. The beetles are much more 
active than the meal-feeding tenebrionids. When they were exam- 
ined some were usually to be seen moving about on the meal and 
frequently they tried to climb the sides of the jar, although making 
little progress. Although they crawled into the meal for conceal- 
ment, for warmth, or for oviposition, they do not, like Tribolium, 
burrow or excavate galleries. On the contrary, they form shallow 
pits or depressions, several beetles occupying the same pit in partial 
concealment. The eggs are deposited on the surface of the meal. 
In one lot of insects of this species kept under observation, an equal 
number of Tribolium also lived and in perfect harmony. Neither 
species showed the least signs of being even in the slightest degree 
predaceous upon the other. 
Even with limited material for observation, it soon became mani- 
fest that this grain beetle is quite capable of breeding freely in a 
moderately cool temperature. Beetles began pairing during the first 
week of April and daily during the warm weather following, but it 
was noticed that they had already deposited eggs at infrequent 
intervals during the winter, as a number of larvae of varying sizes, 
observed in April, bore witness. The living imagos, seven of which 
remained alive in the first jar, were now removed to a different jar 
and placed by themselves. By this time, April 6, some of their 
progeny were about half-grown larvae. Of these, the most mature 
transformed to pupae May 1 and to imagos May 10, the remainder 
continuing as larvae until considerably later. 
From another lot of specimens segregated in a second rearing jar 
and kept in a warm room, it was found that from December 5 to 
April 10 one adult had issued and many pupae were present. This 
gives a full life cycle of eighteen weeks, or four and one-half months, 
the dry artificial atmosphere probably accounting for the slowness of 
development. 
It has always been noticed that when the larvae are disturbed they 
have a habit of rolling up into a ball and remaining thus for a minute 
or more before resuming their usual activity. 
When fully mature, larvae were observed to come to the surface 
of the meal in the rearing jars to transform. Save for close observa- 
tion, the true method of pupation might have escaped notice. When 
the contents of one jar became too dry, a bit of moistened blotting 
