116 



KNOWLEDGE. 



[May, 1901. 



over the damp seawrack, one sees these beetles darting 

 rapidly about ; sometimes they biu'row into holes in the 

 sand. Deeper search among the heaps of seaweed may 

 reveal their grubs (Fig. 2), which are narrow and pointed 

 towards the tail end. the head as in the perfect insect 

 is large and powerful, the legs strong and spin}-, and the 

 body rather strongly armoured. Both beetles and grubs 

 appear to prey on the maggots which feed on the decay- 

 ing vegetable matter found so abundantly in these sea- 

 weed heaps. 



A little assemblage of Eove-beetles, to be looked for 

 almost exclusively below high-water mark, are especially 

 interesting. Actocharis is a genus of only one species — 

 A. Readingii, Sharp — found on our coasts only in Corn- 

 wall and Devon, but occurring also on the French and 

 Sicilian shores. This rare beetle is veiy small, only 

 1.5 mm. (about ,V inch) long and of remarkably narrow 

 form, even for this family (Fig. 1). This fragile little 

 insect, covered with a dense silky pubescence, and with 

 its unarmed legs very broad and flat, oilers a strong 

 contrast to the powerful and spiny Catius. Some of its 

 characters — such as the incomplete fusion of the jaair of 

 jaws (second maxilla") forming the " lower lip — mark it 

 as a very ancient type. 



The species of "Phytosus are not quite so small as 

 Actocharis. Their shape is characteristic, the hind- 

 body widening towards the tail-end, and the feelers being 

 relatively very short. Three kinds — P. spinifer, Ciu'tis, 

 P. balticus, Kraatz (Fig. 5), and P. nU/riieiitris, Chev., 

 inhabit our coasts ; these little beetles tly in the sun- 

 shine. The first^named is often found running on rocks 

 or shingle, while the two latter usually jirefer to lurk 

 inider seaweed or refuse ; a dead starfish often serves 

 both as shelter and food for a large colony. These 

 beetles occur all along the coasts of western Europe and 

 north-western Africa; other kinds inhabit the shores 

 of North America, and the genus reappears far away in 

 the southern seas on the Falkland Islands and Kerguelen. 

 Long considered as exclusively maritime, Phytosus (P. 

 balticus (has lately been discovered almost in the centre 

 of Ireland — that country of ancient survivals — on an 

 islet in the freshwater reaches of the middle Shannon. 



Fig. 4. Fig, 5. 



FiQ. 4. — Grub of Phi/tosus niffriventris. (Aft«r Fauvel.) 

 JIaguified 24 times. 



FiG. 5. — Phyiosux balticus. Magnified 24 times. 



The grub of Phytosus nigriventris has been described 

 by Fauvel.§ It is remarkable in being very like its 



§ A. Fauvel. " Xotice sur quelques Aleocliaricns et description 

 de Larves de Phytosus et Leptusa." Ann. Soc. Enf. France (4), 

 II., 1862, pp. 82-94, pi. II, 



parent-beetle in shape, narrowed at the base of the hind- 

 body and broadened towards the tail-end (Fig. 4), Such 

 a likeness between perfect insect and grub is clearly a 

 sign of antiquity, for the most highly-organised insects 

 are the most unlike the larv» whence they develop. 

 The active, highly organized blowfly, for example, stands 

 in the most extreme contrast to its sluggish degraded 

 maggot. 



(To he continued.) 



MiTlStt 



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ORNiTHOLOGlCA 



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■i5Ci-' 



NOTES:-. 



Conducted by Harry F. Witheebt, f.z.s., m.b.o.u. 



Notes on the Singing of a Song Thrush. — On the 

 24th of March, at 5.30 a.m., a thrush commenced its 

 morning song in a garden at Stroud, where I was stay- 

 ing, and continxied, with pauses of the usual brevity till 

 7 o'clock, when it was silent for rather more than two 

 minutes by my watch; after which it sang till 8.15. 

 It was not in the garden later in the day till 4 o'clock, 

 when it began its evening song. This I did not time ; 

 but I feel sure that it exceeded two hours altogether. 

 The musical range of pitch did not often exceed 3 J tones, 

 saj-. from C up to G. But sometimes an additional 

 higher or lower note was given, so that) thei 

 full range might have been an octave. Probably the 

 bird sang elsewhere during the day, for in 1885 I timed 

 a thrush (a very exceptional singer) for 16 hours in one 

 day. The chief point of interest in such performances 

 is not mere duration of song, but the great variety of 

 the component sounds. In the present instance I 

 counted thirty difierent strains or kinds of songs in 

 the space of a quarter of an hour; and the first two 

 dozen of these were given almost in succession. The 

 last few, however, were heard at intervals in the reitera- 

 tion of the commoner strains. From long familiarity 

 with the subject, I made the record with some con- 

 fidence. One cannot affirm that aU these songs or 

 strains were deliberately modulated ; yet, .when one 

 remembers how much easier it would be for a thrush to 

 repeat one strain time after time, as do the inferior 

 songsters, it is apparent that this pleasing diversity 

 must be intended. And difi^erent thrushes attempt it 

 with unequal success. There is no positive proof that 

 the thrush studies and deliberates in his singing, but the 

 circumstantial evidence to that effect is strong, suggests 

 ing that the bird has a much higher plane of pui-pose 

 and method than the mere prolongation of singing 

 implies. It is remarkable that until the last few 

 years the mimicry of the wild song thrush was never 

 observed, or at least, never recorded. Yet some 

 thrashes mimic almost as distinctly as starlings ; and 

 there are few pleasanter pastimes in warm weather than 

 to rest under a tree in which a thrush is singing, and to 



