April, '06] 



ENTOMOLOGICAL NEWS. 



m 



Cross-section of pericardia! region of l\/r/n>/<i/>//<\ 

 femoratiis d, dorsal diaphragm ; />, pericar- 

 dial cells ; /, 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 

 Acriclid, the common Melanoblus 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 viridissi/na 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 Locustid. 



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 ccrur Hi- i|ii<-lcnirs Oitlmpteres. Comnumknti. m 

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



