244 



SCIENCE 



N. S. Vol. XXX. No. 764 



tion. It is to be regretted that the author did 

 not bring out the homology of these two great 

 regions of the notum and devote his energies 

 to the determination of the real boundaries of 

 these regions. 



The interpretation of the origin of the post 

 scutellum or pseudonotum, as he calls it, was 

 suggested by myself in the paper previously 

 referred to, though I can not agree in consid- 

 ering this region belonging more to the seg- 

 ment in front than to the segment behind, 

 particularly when the phragma is considered 

 as part of this interpolated sclerite. 



The great dorsal muscle of flight for which 

 the phragma was developed is probably only 

 a dorsal intersegmental muscle. These extend 

 from the anterior edge of one segment to the 

 corresponding part of the next. The anterior 

 phragma is mesoprescutal, the posterior is a 

 part of the first abdominal segment. The 

 hymenoptera appear to be an exception in 

 regard to the position of the first abdominal 

 segment, only because of the great constriction 

 between the first and second segment. 



It may be impossible on anatomical grounds 

 to locate the division between segments after 

 the articular membrane has become wholly 

 chitinized. The phragma may be, as this au- 

 thor says, a " chitinization of the infolded 

 intersegmental membrane," but if so, why is 

 not the deepest point of the fold the point of 

 demarkation between the segments? 



A more reasonable position would seem to 

 be that the infolding for the attachment of 

 intersegmental muscles marks the posterior 

 boundary of the prescutum that the phragma 

 belongs therefore entirely to the following 

 segment and that with the completion of the 

 chitinization of the articular membrane, the 

 division is lost somewhere immediately an- 

 terior to the phragma. 



The region designated by this author as 

 pseudonotum developed as a chitinization of 

 the articular membrane is probably therefore 

 made up of two elements, one of which is 

 continuous with the prescutum of the follow- 

 ing segment. 



The articulation of the wing has been 

 studied in much detail, but scarcely anything 

 is added to the work of Amans except the 



application of the Comstock-Needham nomen- 

 clature to the veins. The veins are said to be 

 " connected or associated in a very definite 

 and constant manner with the sclerites of the 

 wing base," but speaking of the chief vein in 

 the wing he says : " The base of the radius is 

 nearly always more or less closely fused with 

 the base of the subcosta but it is clearly con- 

 nected also in a great many cases with the 

 anterior end of the second auxiliary. In other 

 examples its head is only contiguous to the 

 third auxiliary." This does not seem to be 

 very definite nor constant. 



The study of the articulation throws but 

 little light on the question of the homology 

 of the veins because of the fact that in all 

 orders except Odonata and Ephemerida, the 

 basal connection of the veins has been dis- 

 turbed to enable the wing to fold back against 

 the body. Indeed the basal connections of 

 the veins are very unreliable and are not de- 

 pended on by any one in the determination 

 of the homologies of the veins. 



The presenting of theories is condemned by 

 the author in numerous places and this article 

 is ofi^ered as an accumulation of facts and 

 conclusions, but it is very difficult to see the 

 distinction. Theories in truth constitute the 

 whole of science. Facts are nothing unless 

 they mean something, and our interpretation 

 of that meaning is what we really present. A 

 drawing is at best a crude representation of 

 the object and its only use is to represent our 

 theory of what we see. The present paper 

 contains over two hundred excellent drawings 

 with very full explanations which will enable 

 subsequent students to comprehend exactly 

 what the interpretation of the structures were 

 and I feel sure that in most particulars they 

 will concur with his conclusions. 



c. w. woodworth 



University of California 



A Short Handbook of Oil Analysis. By Au- 

 gustus H. Gill, S.B., Ph.D. Fifth Edition. 

 Philadelphia, Lippincott & Co. $1.50. 

 A book on chemical analysis which has five 

 editions in twelve years is very nearly be- 

 yond criticism; fault finding is disapproved 

 in advance, and praise is but gilding the re- 



