October 1S03. 



PSYCHE. 



539 



THE PRIMITIVE NUMBER OF MALPIGHIAN VESSELS IN 



INSECTS.— V. 



BY WILLIAM MORTON WHEELER, PH.D., CHICAGO, ILL. 



Neuroptera. Leon Dufour*, Frey 

 and Leuckartf, v. Siebold \ and 

 Schindler§ have shown that members 

 of this order have either 6 or S Malpi- 

 ghian vessels. The imaginal Sialis 

 has 6 vessels and the same number of 

 discrete proctodaeal diverticula is es- 

 tablished in the embryo, as I have 

 observed in 6'. hiftimata. In what 

 I take to be the young larva of Cory- 

 dalis cornuta there are also 6 vessels 

 but in other much larger larvae (possi- 

 bly belonging to the genus Chauliodes) 

 I find the unusual number 7. This 

 insect, therefore, constitutes a transi- 

 tion to the forms with S vessels, such 

 as Myrmeleon and Hemerobius. 



Paxorpata. The Scorpion flies 

 (Panorpa) agree with Sialis in possess- 

 ing 6 vessels. 



Trichoptera. Patten || has shown 

 that the embryo Xeophylax concinmts 

 develops 6 Malpighian vessels as dis- 

 crete proctodaeal diverticula. This 

 number seems to be retained through- 

 out life by all the species of the order. 



*1. c. p. 565. 

 t 1. c. p. 101. 



I 1. c. p. 627. 

 §1. c. p. 628. 



II The development of phryganids, with a preliminary 

 note on the development of Blatta germanica. Quart, 

 journ. micr. sci. vol. xxiv, 1SS4, p. 590. 



Coleoptera. Schindler * makes 

 the following general statement in re- 

 gard to this order : " Vier Malpighi'sche 

 gefiisse linden sich durchgehends bei 

 den Pentameren, wogegen den Hetero- 

 meren, Tetrameren und Trimeren stets 

 sechs zukommen." This assertion ap- 

 pears to require some qualification, 

 since the Pentameron Hydrophilus has 

 6 Malpighian vessels according to 

 Vangel t while the Heteromeron Sitaris 

 has only 4 according to Beauregard. } 



These are very briefly the facts 

 derived from a study of the embryo : 

 in the greater number of forms the 

 vessels arise as 6 discrete diverticula 

 of the hind-gut. This has been shown 

 for Doryphora by myself*;, for Melo- 

 lontha by Voeltzkow || and for Hydro- 

 philus by Heider.f In the embryo 



*1. c. p. 629 (foot note J. 



f Beitriige zur anatomie, histologic u. physiologic des 



verdauungsapparates des \vasserkaf«rs (Hydrophilus 

 piceus, L.) Nat. hefte. Pest. bd. io, 1SS6. 



\ Recherches sur les insectes vesicants, i partie, 

 anatomie. Journ. ar.at. phys. Paris. 21. Annte 1SS5- 

 1SS6. 



§The embryology of Blatta germanica and Dory- 

 phora decem-lineata. Journ. morph. vol. iii, n 

 1SS9. 



|| Melolontha vulgaris. Ein beitrag zurentwickelung 

 im ei der insecten. Arb. a. d. zool. zoot. inst. in 

 Wiirzb. bd. ix. heft 1. 1SS9. (Plate v. figs 1 , 2 & 13.) 



IT Dieembryonalentwicklung v. Hydrophilus piceus, 

 L i. theil. Jena. 1S89. 



