July 21, 1916] 



SCIENCE 



105 



should be right side up that they may be read 

 without the necessity of removing the specimen 

 from the tray or case. In no instance should 

 flies be gurnrned or mounted in any manner on 

 cards, which are certain to obscure important 

 characters. 



Bevision of other recommendations which 

 occur in the preface should be made. Eine- 

 mesh bobbinet is the proper material for nets; 

 and white is the preferable color, facility of 

 locating the fly in the net after capture out- 

 weighing any element of alarm to the fly prior 

 to capture. In fact, the white net is very at- 

 tractive to many flies, rare species often alight- 

 ing thereon voluntarily in the field. As to 

 size, the 22-inch diameter bamboo ring set in 

 an unjointed three-foot light wooden handle is 

 the most effective, specimens rarely escaping it 

 even if the cast is made during flight. This is 

 the net used by the veteran English field- 

 naturalist, Mr. A. E. Eratt, in South America 

 and ]STew Guinea. It is sufficiently light to be 

 easily wielded in one hand, and perforins ex- 

 ceptional service. 



The fly is best transferred directly from the 

 net to the cyanide vial. The latter should be 

 the 25 x 100 mm. flat-bottom clear-white shell 

 vial, the cyanide enclosed in a wad of tissue 

 paper and tightly wedged into the bottom, 

 shredded tissue paper being placed loosely in 

 the vial to prevent undue rubbing and contact 

 of specimens, and closed with a soft cork 

 stopper. Large and small flies should go in 

 separate vials; such forms as bombyliids with 

 pile that is easily detached must be kept sepa- 

 rate, as well as culicids and other forms that 

 might be injured by stouter flies or that might 

 mess others with their scales, pile, exudations, 

 or pollen. The judgment of the collector must 

 guide him, and he should carry a liberal supply 

 of the vials. The specimens may be left all 

 day in such vials without injury, but should be 

 pinned the same evening or at latest next 

 morning. In dry climates they will not last 

 well over night. 



In giving measurements of flies, the length 

 of one wing, and not the expanse, should be 

 stated. The expanse is not a stable quantity, 

 due to drying and faulty spreading; moreover, 



the wings of study material should not be 

 spread. 



As to the classification adopted, it is espe- 

 cially important to present a correct system in 

 a work intended for beginners. Most sys- 

 tematists will criticize the inclusion of the 

 fleas with the Diptera. The superfamily Mus- 

 coidea is made to include the entire calyptrate 

 and acalyptrate divisions. The superfamily 

 name Cypseloidea should be applied to the 

 acalyptrate groups, while Muscoidea should be 

 restricted to the higher calyptrates. The Mus- 

 coidea of the author are stated to produce ova 

 as a rule, but there are very extensive groups 

 of the higher calyptrates that deposit larvae ; in 

 fact, the larvipositing species of calyptrates 

 will probably easily exceed in number the ovi- 

 positing species. The Nematocera has re- 

 cently been shown by Knab and others to be 

 an unnatural group. In the pages of half-tone 

 reproductions, the Cyclorrhapha are divided 

 into Froboscidea and Eproboscidea, the latter 

 comprising the Fupipara as opposed to all the 

 other Cyclorrhapha; an unnatural arrange- 

 ment, since the main Fupipara show close 

 affinity with the Cypseloidea and not with the 

 Syrphoidea. The Phoridae are wrongly in- 

 cluded in the acalyptrate series. The Bomby- 

 liidse, and not the Braulidse, are commonly 

 termed " bee-flies." 



With these few friendly criticisms, the book 

 is commended as a very useful means of pre- 

 senting objective instruction in dipterology. 

 Charles H. T. Townsend 



SPECIAL ARTICLES 



A SIMPLE AND RAPID METHOD OF STUDYING 



RESPIRATION BY THE DETECTION OF 



EXCEEDINGLY MINUTE QUANTITIES 



OF CARBON DIOXIDE 



In order to arrive at a satisfactory knowl- 

 edge of life-processes, it is necessary to have 

 accurate quantitative methods by which the 

 measurement of these activities can be made. 

 One of the best means of accomplishing this 

 is found in the study of respiration. The pro- 

 duction of CO. is regarded 1 as the only reli- 



i Cf. Tashiro, S., Amer. Jour, of Physiology, 32 : 



