March 23, 1883.] 



SCIENCE. 



203 



haemaglobin. Lankester's second specimen had 

 only one genital papilla and orifice, instead of two, 

 and contained five males, wliicli live, as in Bonellia, 

 as niinnte parasites on tlie female. Tlie male is pro- 

 vided witli a pair of large genital setae, altliough sucli 

 are wanting in the female. — {Ann. mag. not. hist., 

 xi. 37.) c. s. M. [452 



Myriapods and araclimds. 



The blastopore and mesoblast of Peripatus. 

 — The late Prof. Balfour was engaged, just before 

 his death, upon a monograpli on the anatomy and 

 development of Peripatus, and left a series of notes, 

 completed manuscripts, and drawings, which it is in- 

 tended to publish in the Quarterly journal of micro- 

 scopical science for April next. Some of the results 

 have been presented as a preliminary note to the 

 Koyal society of London. 



The results are briefly as follows: that a widely- 

 open slit-like blastopore is formed in the early oval 

 embryo. The blastopore, which occupies the median 

 ventral line, becomes closed in its centre, an anterior 

 portion remaining open as a mouth, while a posterior 

 portion apparently becomes the anus. The meso- 

 blast is formed from the entoderm at the lips of the 

 blastopore, and makes its appearance as a series of 

 paired hollow outgrowths from the cavity of the 

 archenteron. — (Joum. microsc. soc. Zond., Feb., 

 1S83, 52.) c. s. M. [453 



Eyes of Scorpio and Liraulus. — E. Pay Lan- 

 kester and A. G. Bourne have investigated the mi- 

 nute structure of the eyes in Limnlus and Scorpio, 

 and conchide that the results, which are given in 

 detail and with elaborate illustrations, confirm the 

 opinion previously expressed by Lankester, that the 

 scorpions and king-crabs are closely allied repre- 

 sentatives of the class Arachnida. The compound 

 lateral eyes of Limulus are compared with the lat- 

 eral groups of simple eyes in scorpions, and found 

 to agree in the most essential points. The central 

 eyes of Limulus are found to agree still more closely 

 with those of scorpions. — {Quart, joum. microsc. 

 sc, Jan., 188.3.) s. i. s. [454 



lEsects. 

 The scales of Coleoptera. — Mr. George Dim- 

 mock described the scales, or scale-like hairs, of a 

 number of beetles, and considered the effects of scales 

 on the coloration of these insects, and the modes of 

 coloration of scales tliemselves. Scale-like hairs of 

 Cifiudela. Psiloptera, Anthrenus, Hoplia, Polypliylla, 

 Valgus, Clialcolepidius,Alaus, an undetermined genus 

 of European Elateridae, Ptinus, Clytus, and Entimus, 

 were described. This adds the Elateriilae and Ceram- 

 bycidae to tbe families which were already recorded 

 as sometimes owing their figuration to a scale-cover- 

 ing. The influence of air in producing silvery and 

 milky whiteness in insects and in their scales was 

 also discussed. The author adopted Dr. H. A. Hagen's 

 division of the colors of in^ects into 'optical' and 

 'natural' colors of two sorts, — 'dermal' and 'hypo- 

 dermal,' — anil gave a table of treatment with re- 

 agents, to enable one to distinguish these colors in 

 scales under the microscope. As far as examined, 

 scales of Lepidoptera owed their coloration to optical 

 and hypodermal colors; scales of Coleoptera, to opti- 

 cal and dermal colors; allhough too much stress must 

 not be put upon tlie differences between ilermaland 

 hypoilermal colors. The paper, which will appear in 

 full in Psyche, was illustrated by numerous figures 

 and microscopic pieparations. In conclusion, a mode 

 of collecting together scales, or other minute objects of 

 similar nature, on a microscope slide, was exhibited. 



This consists in putting the scales in a drop of some 

 quickly evaporating substance — chloroform is best 

 for most purposes — on the slide. The scales will 

 form in a kind of whirlpool, nearly all the scales 

 finally settling down, as the liquid evaporates, in one 

 place on the slide. This mode of operating is very 

 convenient; and, by inclining the slide gently, the 

 mass of floating scales can be made to settle on the 

 exact centre of the glass. One part of Canada bal- 

 sam to several hundred of chloroform will cause them 

 to stick to the slide. — {Cambr. ent. club; vieetinq 

 March 9.) [455 



Mimicry of humming-birds by moths. — The 

 striking resemblance in size, form, and movements, 

 of the South-American Macroglossa Titan to hum- 

 ming-birds, which has been noticed by Bates, Fritz 

 Muller, and othei'S, and referred to the similarity in 

 their habits,- is believed by Dr. Krause to be a case of 

 protective mimicry; the moths benefiting by their re- 

 semblance to the birds, which have few winged ene- 

 mies. The closeness of the resemblance is supposed 

 also to protect the moths from the humming-birds, 

 which always give chase when they recognize them. 

 To do away with an objection that might be urged 

 from the similar appearance of European Macroglos- 

 sae, which have no Trochilidae to imitate, it is as- 

 sumed either that these birds occurred in Europe in 

 late tertiary times, or that the moths are recent im- 

 portations from the new world. ■ — {Kosmos, Nov.) 

 w. T. [456 



(Economic entomology.) 



The regulative action of birds upon insect 

 oscillations. — The question "Do birds sometimes 

 vary their diet so far as to neglect their more usual 

 food, and take extraordinary numbers of those species 

 of insects, which, for any reason, become superabun- 

 dant for a time ?" is answered by Prof. Forbes in a 

 very conclusive manner. He selected an orchard 

 which had been for some years badly infested by canker- 

 worms; shot a considerable number of birds therein 

 for two successive years (54 birds of 24 species the 

 first year, and 92 birds of 31 species the second year), 

 representing nearly all the kinds seen in the orchard; 

 made full notes of the relative abundance of the 

 species; examined carefully the contents of the stom- 

 achs obtained, with reference not only to the presence 

 of canker-worms, but of all other insects as well ; and 

 tabulated the results. The summaries on these tables 

 are brought into comparison with those deiived from 

 birds of the same species shot in ordinary situations 

 during the same month. Thirty-six species of birds 

 were taken in the infested orchard. 72% of the species, 

 and 60% of the specimens, had eaten canker-worms. 

 3.5% of all the food eaten by all the birds was canker- 

 worms. The comparisons made between the food of 

 these birds and that of birds shot in other situations 

 show, that the large proportion of the food which the 

 canker-worms constituted, in one case was compen- 

 sated by a general diminution of the ratios of all the 

 other kinds of food, and not by a neglect of one or 

 two alone. Hence the birds, in checking the increase 

 of the canker-worm, were not tending to allow an un- 

 due increase of any other species of insect. — {Bull. 

 III. lilate lab., i^o. 6, Dec, 1SS2.) J. H. c. [457 



Corn-root -worm. — The eggs of Diabrotica lon- 

 gicornis have been discovered by Prof. Forbes. They 

 are laid in September and October in the ground 

 upon or about the roots of corn, and probably do not 

 hatch until the following May or June. The best 

 means of checking the increase of this insect is, there- 

 fore, rotation of crops. — {Prairie farmer, Dec. 30, 

 1SS2.) J. H. c. [458 



