480 The Museum Mite. [ August, 
ish grayish masses; secondly, of the eggs in course of develop- 
ment, and of empty shells of hatched eggs, of open and bent 
shells, cracked often longitudinally ; thirdly, of young larve and 
of nymphs, always more numerous than the’ adult animals ; 
fourthly, of tegumentary envelopes proceeding from the moulting 
of a great number of larvæ and nymphs; fifthly, of visceral or 
muscular remains of the body, of pieces of trachex, of striated 
muscular fascia, of dried fragments, sometimes of eggs which 
have not been laid, and which have become loose in the body of 
the females of the attacked insects. 
In the dust at the bottom of the boxes, amongst the remains 
of all kinds, antennz, feet, palpi, broken or fallen, one sometimes 
finds the envelopes of Gamasus, of Glyciphagus, and of Cheyletus 
Acarids, which live also in collections. Upon the insects them- 
selves, and devouring the excrements and the remains of the Ty- 
roglyphus, M. Perris has found, at Mont-de-Marsan, the larve 
of the Cecidomyia entomophila. The walk of the Tyroglyphus 
entomophagus is slow. It walks with the head bent down, in 
such a way as to allow the ridge of contact of the two mandibles 
which go beyond the hairs of the nape of the neck to be seen in 
front. The males are as numerous as the females, and a little 
more’ agile. 
It remains to say a few words as to the best means of keeping 
these mites out of collections, and of getting rid of them when 
they have once effected an entrance. The insects which are most 
liable to be attacked by the Tyroglyphus entomophagus are, as 
already said, those which have not been well dried, or whic 
have been placed in ill fitting boxes in a damp room. 
When the Tyroglyphus has attacked an insect, one perceives 
outside little whitish points on the bodies of those with smooth 
teguments, or on another kind a sort of grayish white powder 
mingled in the hairs of cottony or downy kinds, Soon under the 
insect invaded, or on the corresponding sides of the box, one no- 
tices a matter of a grayish pulverulent aspect, recalling the efflo- 
rescence of saline matters not deliquescent. This dast is said to 
be quite different from the organic pulverulent debris which re- 
sults from the ravages of the Anthrenus or Dermestes ; these lat- 
ter produce a fine sawdust, blackish or brownish, but dry and 
non-adherent. Collections in the south of France, exposed to 
damp, are very rapidly attacked by Tyroglyphus entomophagus- 
The mouldiness which shows itself in a collection makes one sus- _ 
picious of mites, for mould and mites almost always go together- 
