1915 ENTOMOLOGICAL SOCIETY. 67 



with amber-red tips. The edge of tlie ca^^ity is fringed with half a score of 

 pointed, fleshy festoons, which diverge like the spikes of a coronet. The creature 

 can close or open this diadem at will by bringing the denticulations together or 

 by spreading them out wide. - This protects the air-holes which might otherwise be 

 choked up ^^''hen the maggot disappears in the sea of broth. Asphyxia would super- 

 vene, if the two breathing-holes at the back became obstructed. Durin^g the im- 

 mersion, the festooned coronet shuts like a flower, closing its petals and the 

 liquid is not admitted to the cavity." 



" Enclosed in her pupa, the nascent fly begins by hursting the lid of her 

 casket with a hernia whicli comes beween her two eyes and doubles or trebles 

 the size of her head. This cephalic blister throbs: it swells and subsides by turns, 

 owing to the alternate flux and reflux of the blood. It is like the piston of an 

 hydraulic press opening and forcing back the front part of the keg. 



" The head makes its appearance. The hydrocephalous monster continues the 

 play of her forehead, while herself remaining stationary. Inside the pupa a deli- 

 cate work is being performed : the casting of the white nymphal tunic. All through 

 tliis operation, the hernia is still projecting. The head is not the head of a fly, 

 but a queer, enoraious mitre, spreading at the base into two red skull-caps, which 

 are the eyes. To split lier cranium in the middle, shunt the two halves to the 

 right and left, and seiid surging through the gap a tumour which staves -the 

 barrel with its pressure : this constitutes the Ay's eccentric method, 



" For what reason does the hernia, once the keg is staved, continue swollen 

 and projecting? I take it to be a waste pocket into which the insect momentarily 

 forces back its reserves oT blood in order to diminish the bulk of the body to that 

 extent and to extract it more easily from the nymphal slough and afterwards from 

 the narrow channel of the shell. As long as the operation of the release lasts, it 

 pushes outside all that it is able to inject of its accumulated humours; it makes 

 itself small inside the pupa and swells into a hloated deformity without. Two 

 hours and more are spent in this laborious stripping. 



" At last the fly comes into view. The wings, mere scanty stumps, hardly 

 reach the middle of the abdomen. On the^ outer edge they have a deep notch, 

 similar to the waist of a violin. This diminishes by just so much the surface and 

 the length, an excellent device for decreasing the friction along the earthy column 

 which has next to be sealed. The hydrocephalous one resumes her performance 

 more vigorously than ever; she inflates and deflates her frontal knob. The pounded 

 sand rustles down the insect's sides. The legs play but a secondary part. Stretched 

 behind, motionless, when the piston-stroke is delivered, they furnish a support. 

 As the sand descends they pile it and nimbly push it back, after which they drag 

 along lifelessly until the next avalanche. The head advances each time iby a length 

 equal to that of the sand displaced. Each stroke of the frontal swelling means a 

 step forward. In a dry, loose soil, things go pretty fast. A column six inches 

 high is traversed in less than a quarter of an hour. 



" As soon as it reaches the surface the insect, covered with dust, proceeds to 

 make its toilet. It thrusts out the blister of its forehead for the last time, and 

 brushes it carefully with its front tarsi. It is important that the little pounding- 

 engine should be carefully dusted before it is taken inside to form a forehead that 

 will open no more: this lest any grit should lodge in the head. The wings are 

 carefully brushed and polished ; they lose their curved notches ; they lengthen and 

 spread. Then, motionless on the surface of the sand, the fly matures fully." 



I could give many more passages from Pabre's delightful '* Souvenirs Ento- 



