A beautiful stamp

 The 20 centavos large format cattle is one of the most beautiful stamps ever issued. Not only is it a beautiful design, it was also a regular definitive, a "lowly" definitive. 

The stamp was issued in 1942, and is found on the 1E3 paper (previous two blocks), 1E4, 2D (straight rays diffused paper of 1943), 2D, and 1L. Below is a section of a 2C block.

Here is a somewhat random selection of covers bearing this stamp. The usage period, 1942-1951/2, coincides with World War II and a few years after.

Three 1942 covers with the 1 peso red airmail stamp

 The airmail issue of the 1940s received a lot of combined use with the 1935-51 definitives. Here are three covers with the 1 peso value, all to the US, all censored.

This cover bears a 15cJMG stamp.

Two 1942 covers to the US bearing the 15cJMG

 Both censored, as expected. The earliest printing of the 15cJMG on one of the 1E3 papers was printed in a small run. The 15cJMGs on these two covers may be from that printing.

Two 'cents' covers to the US from 1942

 Censored, as expected. This cover has a rare combination of stamps to make 15 centavos (12+3).

This cover bears commemoratives from that year.

The 35c value is sometimes include as one of the 1935-51 issues.

A 5 pesos 1942 cover to Sweden

 Censored, as expected.

A 2 pesos 1942 cover to the US

 Censored, as expected. A 6.25 rare rate.

Two 1942 covers to the US, one by air, the other one by ship

This first cover has the very rare small 'Passed US Censor' marking. The yellowing along the left edge I believe is not from a missing censorship tape, just good old yellowing. The covers with this marking were not taped along the edge.

Here is a ship cover.

Two 1942 covers to the US with uncommon stamp combinations

 Any 1.15 pesos rate that is not fulfilled with the usual 1 peso and 15cSC of the time is uncommon.

Two 1942 1.15 pesos rates to the US

 This use is most common. This first cover does not seem to have passed though the censorship office.

And this one certainly did.