38 OUR HOUSEHOLD INSECTS 



British fauna, having been introduced here with foreign 

 merchandise. They have, however, established them- 

 selves, at least under the shelter of human roofs, where 

 they will breed freely, and therefore, though they do 

 not yet appear to have become naturalised in the truly 

 wild condition, they are usually included in lists of 

 British insects. 



They are so much alike that to a casual observer they 

 would appear identical. By a very close and careful 

 comparison under the microscope, minute points of dif- 

 ference in the antennae, thorax, and punctuation can be 

 made out, but these are of too minute and technical a 

 character to be rendered intelligible here. In the name 

 confusum, the " confused," given to the second species, 

 we have an indication of the difficulty that attends their 

 separation, and of the probability of their being con- 

 founded together. There is one peculiarity, however, 

 possessed in common by these insects and their allies 

 which is worth notice; it is that the eyes, which look like 

 piles of tiny, polished, black beads, are much encroached 

 upon by a projecting ridge in front of the head, which is 

 produced backwards in such a way as to appear to have 

 grown partially across the eyes, almost entirely dividing 

 each mass into two unequal parts, one above, the other 

 beneath. 



The larvae of these insects are tolerably active, some- 

 what hairy creatures, with six short legs in front. In 

 common with larvae generally, they change their skin 

 several times, each time making their exit from the 

 slough through a slit along the back of the neck, drag- 

 ging out therefrom, first the segments that afterwards 

 become the thorax, then the head and legs, and finally 

 the abdomen. 



Previously to assuming the pupal form, they become 



