252 



HA RB WICKE'S SCIENCE- G OSSIP. 



during the warmer months of the year only, but in 

 the season of 1S84 it was taken rather plentifully 

 during August, as late as 7 o'clock P.M., and during 

 the warmer hours of the day it could be frequently 

 met with as late as October. Possibly the extra- 

 ordinary wave of heat which passed over this country 

 during the summer of 1SS4 may have tempted this 

 creature (like many others) to indulge in the prolon- 

 gation of its appearance in public. They associate 

 seldom in large numbers, but appear to be of a 



pseudo-tracheoe ; they are super-imposed, and have 

 their margins crenulated. They are quite hyaline 

 in appearance ; polarised light does not affect them. 

 Those which most nearly approximate to the pseudo- 

 trachere are very deeply indented — giving the appear- 

 ance of being a separate plate to each false ring ; 

 the broader bands are less deeply indented. 



Both sets run parallel with the pseudo-tracheae 

 throughout their entire length. There are also other 

 organs within the lobes, the precise object of which has 



SCALE OF IO0O T -S OF AN INCH. 



Fig. 162. — Central portion of dental organs of Musca meridiava. 



somewhat solitary turn of mind, supposing them to 

 possess such. 



The expanded lobe of the labrum is undoubtedly a 

 very fine object as a type of this class of mouth. The 

 pseudo-trachece are not correspondingly large, nor 

 are they as numerous as may be met with in some 

 families of this order ; but the intervening spaces 

 show, in a remarkable manner, the supporting mem- 

 branes which give the necessary stability to these 

 organs, and, very possibly, control their movement, 

 which appears to be requisite for collecting and 

 conveying the food on its journey to the oesophagus. 

 These membranes are two in number for each 



not been quite made out by the writer. They consist 

 of tolerably broad plates of what appears to be 

 colourless chitine, as they polarise feebly. They are 

 about ten or twelve in number, joined together at 

 their base, which part occupies a position immediately 

 adjoining the basal portion of the teeth, they extend 

 towards the margin of the lobes and probably 

 their use is to expand them, thereby causing the 

 individual rings of the pseudo-trachea; to separate 

 for the admission of food, while the supporting mem- 

 branes may be capable of bringing them together, 

 and thus force the enclosed liquid food into the 

 main channel 



