Sentence:  The origin of the first and second median <WSD>nervules</WSD> corresponds to that of the two superior subcostal <WSD>nervules</WSD>; and the <WSD>nervule</WSD> closing the cell unites with the apical portion of the median <WSD>nervule</WSD> at a right angle. 
Meaning of the word marked with <WSD> tags:  A minor vein in a wing of an insect.