HARDWICKE' S SCIENCE-GOSSIP. 



1 1 



may say, fully three hundred specimens of the 

 clouded yellow were taken in my net last summer, of 

 that number five only being females. I was struck 

 by this disparity early in August, and with the idea 

 of testing the point for the whole season I netted 

 every possible specimen, subsequently granting 

 liberty to those for which I had no purpose. My 

 observations on the extreme scarcity of the female 

 insect have likewise been established by the 

 observations of many correspondents, who have sent 

 me interesting particulars from all parts of the four 

 western counties. This peculiarity cannot be ac- 

 counted for by a tendency, on the part of the female, 

 for resting, because I happen to have a good eye 

 for insects, and it stands to reason that I could see 

 the female resting, as readily as I could her lover. 



There were just two other well-marked features in 

 connection with the habits of edusa, which struck 

 -me, but which have received no notice from the 

 writers in Science-Gossip, or from the many 

 observers who have written to me. When netting in a 

 clover-field, where the flowers were mostly white or of 

 a whitish tendency, the clouded yellow invariably 

 rested on bare patches of the soil, where it simulated 

 the hue of its resting-place so admirably, as to give 

 very sharp eyes a difficulty in detecting it. Where 

 yellow flowers were prevalent, such as trifoliums and 

 ragwort, it chose these for its resting-place, leaving 

 the soil and white and pink flowers severely alone. 

 And again, in meadows where the corn was stacked, 

 and the soil was carpeted with a fresh after-growth, 

 the stacks were the principal places of rest. So 

 defined were these selections, and so nicely did they 

 conform with the colours of the insect, that many 

 •desirable specimens basked before one's eyes in 

 perfect bliss, enjoying immunity from capture. On 

 September 20th, although I was positive about the 

 place where I saw the insect alight, I missed a 

 beautiful specimen of Colias hyale, Linn., the only 

 .one I saw for the season, on account of the con- 

 formity of its colour with the place where it alighted. 



In addition to this choice of position when resting, 

 (the clouded yellow has shown a marked partiality for 

 frequenting low-lying grounds, where it had full 

 advantage of the sun, and was sheltered from all 

 unkindly winds. Not twenty of all the specimens I 

 saw last summer, occurred on the hill-sides or the 

 breezy uplands. Absence or presence of food-plant 

 will not account for this, for the whole country 

 generally was ablaze with clover, during the months 

 when the insect was prevalent ; while many a 

 •brilliant clover-field with a breezy situation, proved 

 a barren hunting-ground, during the time that edusa 

 gladdened more sheltered positions. Hence I am 

 inclined to think that, in spite of its strength of flight 

 and endurance while on the wing, it is not a general 

 lover of breezy situations. 



Some time back my friend, Mr. Crowther, 

 mentioned the fact, that while the clouded yellow 



was almost as common in Cornwall last summer as 

 during the summer of 1877, the characteristic of the 

 latter year had not been repeated, by the insect 

 appearing in "flights." This is substantially true. 

 For while the insect was seen in unusual numbers, no 

 approach to the feature which made 1877 so famous 

 to entomologists was noticed. I think its appearance 

 in this valley was as striking as any records I have 

 yet seen from other places ; yet there was not the 

 least indication on any occasion of the insect coming, 

 gambolling, or going in flights. 



ON THE UNDERGROUND GEOLOGY 

 OF LONDON. 



No. II. 



By Edward A. Martin, Author of "Amidst 

 Nature's Realms," etc. 



THOSE borings with which we have already 

 dealt in the previous paper on this subject, lay 

 more or less in a direction north and south of one 

 another. They are, however, by no means the only 

 borings from which we are able to acquire useful 

 information in respect to the contour of the 

 underground foundations of the metropolitan area, 

 and we now proceed to deal with those bore-holes 

 which, starting with that at Burford, in Oxfordshire, 

 lie in a line bearing a more or less N.W. and S.E. 

 direction, and which, crossing London, terminates, in 

 England, at Dover. 



We commence at Burford, since here true coal- 

 measures have undoubtedly been met with, and this 

 fact gives us a fair starting-point, from which to judge 

 of our pakeozoic land-surface. 



As in the diagrams which have already appeared, 

 there is uniformity in the thickness and trend of the 

 beds as far down as the base of the gault, after 

 ■ft'hich speculation and "theory have to take the place 

 of ascertained fact. It will be noticed that there 

 appears to be, to a certain extent, a thinning of the 

 chalk as it approaches the surface on the north. 

 This, however, is only apparent in consequence of 

 the exaggerated vertical scale used, as compared with 

 the horizontal scale, and would have no place were the 

 scales identical. It is necessary that this should be 

 borne in mind. We have seen that at Meux's in 

 Tottenham Court Road, the appearance of 64 feet of J» 

 Jurasssic beds, which lie immediately above Devonian 

 strata, have to be accounted for. The Jurassic 

 strata will here be met with as an approach towards 

 the thinning out of these beds, which is gradually 

 taking place as we proceed in a south-easterly 

 direction, and which causes the appearance at Cross- 

 ness of beds which remain undecided between 

 Devonian and new red sandstone. In Fig. 14 

 they have been included amongst the former, 

 although it is quite possible that they may be the 

 latter, in which case there would be an at present 



