URBICOLA COMMA. 



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the shell of a hen's egg. The dark micropylar spot composed of minute 

 black scratches or irregular lines (Buckler). Nearly 1mm. in diameter 

 at the base ; in shape exactly resembling a pudding- basin, having a 

 sunken crown, rounded sides, and a well-developed basal rim; the base 

 is quite flat; the surface is finely granulated, forming reticulations near 

 the base which run into ridges to the rim. When first laid the colour 

 is pearl-white with the slightest yellowish -green tinge which very 

 gradually turns deeper in colour, assuming a pale straw -yellow on the 

 6th day, and, when a fortnight old, is of a clear apricot-yellow, which 

 colour it remains until the middle of January, when a slight change 

 begins to take place by the colouring gradually fading until it finally 

 turns to an opaque-white with the faintest yellowish hue at the base, 

 and rather leaden in certain lights on the crown. It remains unchanged 

 during February and March ; at the end of the latter month, or the 

 first few days of April, it hatches. After hatching, the shell is dull 

 opaque- white (Frohawk). [We have seen no egg of this species with 

 a basal rim as here described. Probably this was a case like those 

 (e.g., Colias edusa) described Nat. Hist. Brit. Lep., vol. i., p. 9.] 



Habits of larva. — The young larvae leave the eggs in late March 

 (March 27th) and early April (lst-7th), each one eating a circular hole in 

 the crown of the egg through which it emerges. It is then about 2mm. 

 long, and, if disturbed, immediately rolls itself up, and remains motion- 

 less for several minutes. Directly after leaving the egg it spins the fine 

 grass together into a somewhat dense cluster an inch or two above the 

 ground, living in this shelter and feeding upon the grass surrounding 

 it, remaining almost always completely hidden. Sometimes as many as 

 three or four live together. It appears to be chiefly nocturnal, resting 

 quietly during the day, and is exceedingly difficult to see, so well is it 

 hidden. In some, reared in confinement, the first moult took place 

 May 1st and 2nd, second moult May 28th, third moult about June 

 14th, fourth (and last) moult about July 8th or 9th. All this time 

 they live entirely concealed in the tubes of grass spun closely together. 

 They crawl rapidly either forwards or backwards, similarly to other 

 case-dwellers, and feed on any species of grass that happens to be 

 interwoven with the hair-grass selected for them. If disturbed 

 when crawling, the larva frequently wriggles backwards very rapidly, 

 similarly to the habit of wriggling possessed by many micro larvae 

 (Frohaw T k). The habits of the larva in nature were observed by 

 Staudinger, on a turf-covered sandbank in the Althenthal, in Finmark, 

 in June, 1860. On the 8th, several larvae were found forming, close to 

 the ground between the grass, what may be described as slightly spun 

 passages, ending in a tube formed of gnawed grass-culms, joined together, 

 which were either buried in the sand or fastened under some sheltering 

 object. The first larva was observed as it put its head out of its tube 

 to feed on the surrounding blades of a thick tuft of grass, eating with 



* Gillmer writes that eggs received by him "from Sch\verin-in-Mecklenburg, 

 on August 4th, 1900, were hemispherical in shape, somewhat sunk in on the top ; 

 of a reddish-yellow tint which became after a few days (August 18th) paler yellow, 

 even almost whitish ; although some of the eggs even then remained reddish-yellow. 

 The walls of the egg are netted, the network consists of irregular polygonal cells, 

 which are especially distinct towards the micropylar depression of the summit. 

 The base is flat and without any special characteristic. Diameter of base circ. 

 0*8mm., height circ. 0-65mm.-0-7mm." 



