480 Calendar of Nature. 



cern has no eyes ; two antenrrae proceed from the lower part of the forehead ; 

 it lias six small and brownish-coloured legs ; its body is covered with a strong 

 beetle-like coat, which renders it very difficult to kill ; it is three-jointed, and 

 the wings are something longer than the body : when viewed through a 

 powerful microscope,they appear beautifully reticulated with a plain border 

 fringed with hairs. This fly lodges in the ear, but seldom penetrates within 

 the glume ; but when that is opened by the finger where the moths are, these 

 little black flies, which are scarcely a tenth of an inch in length, and small in 

 proportion, attracted by the smell with which they seem to have been long 

 tantalised, come forward, feeling their way with their antennas, and often 

 pass the caterpillar without seeming to observe it, though within a hair's 

 breadth of touching it; but the moment they do touch the maggot with 

 their forehead they immediately become bent, and fix the anus on any part 

 of the maggot with which they come in contact. The maggot begins to 

 turn itself, and the fly extends her wings to balance herself, and remains 

 about a quarter of a minute, when it moves off* but sometimes returns to 

 repeat the operation two or three times. The fly often dies within two or 

 three days after her eggs are laid, but hitherto we have observed no differ- 

 ence between those maggots that have come in contact with the fly, and 

 those that have been secure from their touch. The ear of wheat becomes 

 parched on the infected side ; the caterpillar escapes and falls to the ground, 

 where it does not remain many minutes before it works itself under cover 

 nearly half an inch deep. Those that have lain a fortnight still move when 

 brought to light. The interest excited here by the ravages of this maggot 

 will excuse the apparent digression. 



Barley which brairded on the 10th of May (p. 285.) came in the ear on 

 the 18th (69 days); mean temperature of that period 55°. The dry weather 

 in May and June caused the barley to spindle, and the ear appeared in the 

 same space of time it did last season, though there were "8° less temperature, 

 (p. 96.) Privet came in flower on the 14th; the Butomus urnbellatus 

 on the 1 5th ; the Xllium candidum came in flower on the 24th, and goose- 

 berries were ripe on the 29th, about a week later than last season : but a 

 week in the end of July is equal to two weeks in the end of September in 

 promoting the ripening process. There were 13 days of partial, and 

 5 days of clear, sunshine: in July, 13 days were cloudy, and there 

 were 10 days on which rain fell. The wind blew from the W., S.W., and 

 N.W. 19 days, and from the E. and N.E. 12 days. The air was exceed- 

 ingly dry before the rains in June, as may be observed by the unusual 

 difference between the mean temperature and point of deposition in the 

 Diagram ; and tender foliage of trees was in consequence much shrivelled. 

 Since the 10th of June the air has been unusually moist, often at saturation, 

 and foliage has a fresh and healthy appearance. The dew point is often 

 some degrees higher than the minimum temperature. On the last night of 

 July it was 52°; minimum temperature 46°: of course the moisture depo- 

 sited in the shape of dew was considerable. 



Errata. — In my last Calendar, p. 284., in the sixth line below the Dia- 

 gram, write the word " under *' after " more than 5°; " in the fourth line 

 from the bottom, p. 285.," JVarcissus on the 56th," should be on the " 30th." 

 Those who have the Numbers will be kind enough to make these correc- 

 tions with the pen. — A. G. 



DiAGBAM, showing the Motion of the Mercury in the Barometer and Ther- 

 mometer, and the Dew Point, or the mean of each, for each ten days in 

 August and September ; also the Depth of Rain in the Pluviometer, and 

 Quantity of Moisture evaporated from the Evaporating Gauge for the 

 same period; as extracted from the Register kept at Annat Gardens, 

 Perthshire, N. lat. 56° 23^, above the level of the sea 172 ft., and 

 15 miles from the coast, by the mean of daily observations at 10 o'clock 

 morning and 10 o'clock evening. 



