76 



prennent un revêtement interne composé dîme intima chitineuse, 

 au-dessus de laquelle viennent deux assises de muscles longitudinaux 

 et annulaires, dont les contractions facilitent l'expulsion brusque du 

 liquide contenu dans le réservoir supérieur. 



En résumé, cet appareil glandulaire, par sa disposition et sa 

 structure, permet de s'expliquer la façon dont est expulsé le liquide 

 que les Brachines lancent brusquement pour se défendre contre leurs 

 nombreux ennemis et se dérober à leurs poursuites. De plus, la pré- 

 sence d'une intima chitineuse, recouvrant les cavités internes du ré- 

 ceptacle et du conduit excréteur terminal, indique nettement l'origine 

 ectodermique de ces deux organes et prouve qu'ils dérivent d'une 

 imagination tégumentaire. 



2. Chromatin Reduction in the Hemiptera: a Correction. 



By Thos. H. Montgomery jr., Dr. phil. (University of Pennsylvania, Philadelphia). 



eingeg. 27. December 1898. 



In two papers on this subject (Zoolog. Anzeiger No. 546; Spen- 

 ge I's Zoolog. Jahrbb. 12. 1898) the first reduction division in the ge- 

 nus EucMstus (Pentatoma) was described by me as a transverse division 

 of the chromosomes, the second as a transverse division also. Since 

 the time of writing of these papers I have had opportunity to study 

 further material of EucMstus, as well as of other genera of the Hemi- 

 ptera Heteroptera, and this study has convinced me that the second 

 reduction division is normally a longitudinal (equational) division, 

 exactly as has been described by F. C. Panimi er (Anat. Anzeiger 

 14. 1898). 



In EucMstus the second spermatocytic division occasionally results 

 in a transverse division of the chromosomes, exactly as I figured it in 

 my second paper, but this mode of division occurs only as a variation, 

 the division being usually longitudinal. In my first studies on the 

 subject the cells of the larger generation of spermatocytes formed the 

 basis for the determination of the reduction divisions, since these cells 

 on account of their much greater size are more favorable for investi- 

 gation. And in the testes of the individual first studied these larger 

 spermatocytes showed as many cases of transverse as of longitudinal 

 splitting of the chromosomes in the metakinesis of the second reduc- 

 tion division. A subsequent examination of more than a dozen testes 

 from other individuals, however, shows conclusively that in the majo- 

 rity of cases, the second division is longitudinal and not transverse, so 

 that those cases figured by me where the daughter chromosomes of 

 the metaphase of the first reduction division are elongated parallel to 



