FURTHER NOTES ON THE EARWIG, 179 



result. As the egg is practically circular in cross section, we can 

 easily calculate the actual bulk, on doing so it appears that the egg 

 just before hatching is more than three and a half times larger in 

 cubic contents than the newly laid egg. The first batch up to six 

 days before hatching increased in bulk nearly two and a half times, in 

 this case, and in the third batch, there can hardly be any question of 

 any of the increase consisting of air in the tracheae as may be the 

 case, when hatching is imminent. The eggs in the nest are not in 

 sufficiently moist surroundings to account for the supply of imbibed 

 fluid apart from the ministrations of the parent earwig. The situa- 

 tion is different from that of various sawflies and some Lepidoptera, 

 whose eggs are within the living tissues of a plant. 



The eggs in a batch usually present several very definitely smaller 

 than the others, with one or two intermediates. I do not know 

 whether these smaller ones are the latest developed. The remainder 

 are, to all appearance, of a uniform size, in the batches selected for 

 eggs measuring the increase of size during incubation, only average 

 were selected for measurement. 



At moulting, the phenomenon, to which I called attention in a 

 paper to the South London Society in 1902, and called inflation, is 

 very evident. After each moult the insect is white and of a larger 

 size than it has, when some time after, its cuticle has hardened and 

 become brown, and it is sufficiently translucent to show that the abdo- 

 men contains a cavity, the alimentary canal, full of air. The differ- 

 ence in size is easily realised when the newly moulted insect is com- 

 pared with its fellows that had moulted a day or two before, it is 

 obviously larger. The following measurements illustrate this : At 

 12.30 p.m. on April 10th, two larvae were observed just moulted for 

 the first time, they measured in length 4-8mm. and 5'2mm. Two 

 hoai's later (at 2.30 p.m.) they were still very white and measured 

 4"Bmm. and 4-8mm. long respectively. At 7.30 a.m. the next morn- 

 ing each was 4mm. long, but had not yet become fully darkened. At 

 1 p.m., after feeding, they were 4-8mm. and 5-Omm. long respectively. 



On June 2nd there Avas a newly moulted male, still quite white, 

 amongst others that had also moulted to the imago state, but had 

 matured in colouring. The note made at the time, is that, the abdo- 

 men from end of wings as closed up to bases of cerci is obviously 

 longer than from head (anterior margin of prothora-x) to end of wings, 

 whilst in those about that are brown, this portion of the abdomen is 

 much shorter than the thoracic piece, it is also thinner and flatter 

 than in the white one, beside which they look pinched and starved. 

 The white one is obviously " inflated." Except the last two segments 

 the abdomen is very translucent and filled with something quite 

 transparent, probably air, which it proves to be when the abdomen is 

 pierced by a needle, when a trace of fluid exudes under pressure, 

 enough to make the air pressed out bubble. The abdomen is then 

 shrunk to the dimensions of those of the other mature imagines. This 

 starved and pinched look is due to their not being yet fed since their 

 change. An earwig, as ordinarily seen, has considerable abdominal 

 contents — food, fat, etc. 



I separated some recently hatched larvae from the rest of the brood, 

 with a view to determining how they would get on without the mater- 

 nal care. They got on fairly well till half-grown, and then several 



