April, 'o6] 



ENTOMOLOGICAL NEWS. 



113 



Cross-section of pericardial region of Melanopius 

 femoratus—d, dorsal diaphragm ; p, pericar- 

 dial cells ; m, malpighian tube ; b, heart. 



A Malpighian Tube Within the Heart. 



By William A. Riley, Cornell University. 



We are accustomed to variety in the location of the urinary 

 organs of the Arthropoda, but one is a little surprised to find 

 a Malpighian tube within the heart. And yet such a condi- 

 tion sometimes occurs among the insects. So far as has been 

 found it occurs only in certain Orthoptera. The accompany- 

 ing illustration from a cross-section of the abdomen of an 

 Acridid, the common Melanofrlus femoratus, shows two cross- 

 sections of a Malpighian 

 tube within the cavity of 

 the heart. On tracing 

 these it is seen that they 

 do not represent two 

 tubes, but rather a sin- 

 gle one which is doubled 

 upon itself. 



Aside from a brief 

 incidental mention by Kowalevsky, 1894,* this condition 

 seems to have escaped notice. In studying the heart of 

 Pachytilus this worker was surprised to find in the mid- 

 dle region of the abdomen, Malpighian tubes within the 

 cavity of the heart. Supposing, at first that it was a pa- 

 thological condition, he studied the same region of the heart 

 of Locusta viridissima and found exactly the same condition. 

 In this species, it was easy to recognize that the Malpighian 

 tube reached the heart by way of the cardio-coelomic aper- 

 ture, and that after a tortuous course it passed through the 

 cardio-pericardial aperture into the pericardial chamber. 

 Later, he found the same condition in the nymph of an unde- 

 termined L/Ocustid. 



As a result of his studies, Kowalevsky reached the con- 

 clusion that this condition was not pathological but perfectly 

 normal for the Acrididae and Locustidae. He sought to ex- 

 plain the strange phenomenon as a case of physiological attrac- 

 tion. In most animals, — Molluscs, Vertebrates, Crustaceans, 



* Kowalevsky, A. 1894. Etudes sur le cceur de quelques Orthopteres. Communication 

 preliminaire. Arch. Zool. exp. 3 ser. t. 2 pp., 485-490. 



